Fall Spice Cake with Bavarian Cream

The Art.
    I once believed this dessert was born out of serendipity, in that I had 6 egg yolks left over from the Blooming Rose Cupcakes the other day, which just so happens to be the number of egg yolks required to make Bavarian Cream. But just when I thought Fate was smiling down upon me, I had to go and make an entire post about troubleshooting the Bavarian cream and thus bought another dozen eggs. C'est la vie I suppose. Since autumn is upon us, I decided to pair the cream with a moist spice cake. Flavored with cinnamon, nutmeg, allspice and clove, this cake combines all of my favorite fall spices. I didn't want to interfere with the harmony between the cake and the cream, so I refrained from making an icing for the cake. Instead, I dusted it with powdered sugar in a leaf pattern to celebrate the season.

The Science.
    This Bavarian cream is made by combining a rich custard with light whipped cream. I previously did some troubleshooting on the custard component, so today I'll talk about cream. Whipping up a fluffy, stable whipped cream can be challenging for many bakers, but if you understand the chemistry of whipping cream it can be a cinch. First, you must select the correct type of cream. Heavy whipping cream with 40% fat is ideal, since higher fat content results in stiffer whipped cream. Some manufacturers go the cheaper route, and instead supplement 30% fat with additives such as carageenan and polysorbate to make stiffer peaks [1]. However, additives just can't replace good old milk fat, and these don't perform as well as the 40% heavy cream. Also, be sure that your cream is pasturized, not ultrapasturized. Ultrapasturization degrades the milk proteins, making the whipped cream less stable [1].
    Second, cold temperature is your friend while making whipped cream. Milk fat consists of mostly saturated fatty acids, which have lipid tails that pack tightly together at cold temperatures [2]. Keeping cream as cold as possible while it's whipped causes the fat to have a thicker consistency, and thus the ability to hold more air than if it is warm. This results in a fluffier, more stable whipped cream. To make the best whipped cream, chill your beater blades and bowl in the freezer before you begin. Place your bowl inside an ice bath while you whip your cream, and make sure you are in a cool area of the kitchen, away from the oven.

The Recipe.

One batch of Bavarian cream, recipe found here. You'll have to plan ahead, because the custard needs to set overnight.

Spice Cake:

2 1/2 cups all purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon salt
3/4 teaspoon cinnamon
3/4 teaspoon allspice
1/2 teaspoon cloves
1/2 teaspoon nutmeg
1 cup sugar
3/4 cup brown sugar
1/2 cup vegetable oil
3 eggs
1 1/3 cups buttermilk
1/2 cup powdered sugar (for dusting)

    Preheat oven to 350^oF. Coat a 9"x13" pan with baking spray. Mix dry ingredients in a large bowl. In a medim bowl, beat together vegetable oil, sugars, and eggs on medium speed. Beat in buttermilk. Add to dry mixture, and beat just until smooth. Pour batter into pan and bake on center rack 45 minutes, or until tester comes out clean. Cool in pan.
    For this project, we want a nice, flat surface on top of our cake to dust our powdered sugar on. If your cake turns out "crowned," meaning it has risen more in the center than on the edges, it is simple to fix.

    Right when you take your cake out of the oven, lay a damp paper towel over the hot cake and gently press all over until the center is the same height as the edges. In the future, you can prevent crowning by wrapping strips of wet towel around the edges of your cake pan before you put it in the oven.

Leaf decorations:
    On a piece of cardstock, draw a leaf stencil approximately 3 inches square. Here is the pattern I used, it's a maple leaf that I drew. Of course, you can draw a much simpler leaf shape to make your life easier. Cut this leaf out and use it to trace 12 leaves.

     Cut your leaf patterns out and place them in a 4x3 grid pattern on top of the spice cake. Generously sift powdered sugar over the cake, until you can't see the surface of the cake. Very carefully lift leaves off of the cake, making sure not to drop powdered sugar back onto the surface.

    You now have 12 cake servings, each with a powdered sugar leaf on top. Do not cover the cake before serving, otherwise the collecting moisture will dissolve the powdered sugar decoration. Cut into squares and serve with a dollop of Bavarian cream. Enjoy by the fire with a hot cup of tea.

1. Galvin, Lori et al. Test Kitchen Favorites. Brookline, MA: America's Test Kitchen, 2006.
2. Larsen, M.K. et al. "Short communication: Within-day variation in fatty acid composition of milk from cows in an automatic milking system." Journal of Dairy Science, Available online 15 August 2012, ISSN 0022-0302, 10.3168/jds.2012-5815.

Lab Bench: Silky Bavarian Cream

The Art.
    Best Friend Hanako has been my steadfast companion on many wonderful baking adventures, but the one I love best is the time we made Bavarian cream. We had just thrown together some spice cake cupcakes, and I had found a new Bavarian Cream recipe for us to use as a filling. As usual, we were focused more on gossiping and giggling rather than baking, and I didn't have high hopes for our end product. We didn't even follow the recipe entirely. However, the resulting Bavarian cream was one of those happy accidents you experience in life that you reminisce about for years to come. It was silky, rich and wonderful. I have attempted to recreate this cream several times with limited success, and each time it falls short of my expectations and I fall into a deep Baking Depression. After my most recent attempt, I decided enough was enough. Today, I will share with you what ensues when a scientist has trouble with a recipe.

The Science.
   This Bavarian Cream is made up of two components: a whipped cream and a vanilla custard. To be honest, the root of all my problems lies within the custard component. I hypothesized that there were a few variables that had changed between the first Bavarian cream and the subsequent batches. First, I know for a fact that I didn't use anywhere near as much gelatin as the recipe calls for. Second, I didn't use a thermometer while cooking the custard, nor record how long I cooked it. (That part really infuriates me.) Third, I'm not sure if I used whole milk or 1%. And fourth, Best Friend Hanako reminded me that I had originally chilled it overnight, because I knew she would have no patience for stirring over a double boiler when she came over.
     Custards can be very sensitive to heat, and according to those who know, they should only be cooked to 170-175^oF [1]. Any higher, and the eggs will begin to "break," and you'll end up with a lumpy custard. Straining through a sieve will only take out large clumps caused by under-stirring, so there's no going back after your eggs have curdled. For this recipe, I needed to figure out the perfect cook time, thickening agent, and chill time to create a custard that is thick enough to be stable once blended with the whipped cream, yet gently cooked so it maintains a rich, silky texture. 
    After several days of painstakingly altering the custard recipe, I finally got fed up with the whole thing, and decided to take a step back. I remembered when my Aunt first taught me to make custard, and threw all the custard ingredients together in a pan and stirred constantly with a spatula. When the mixture just started to bubble (which I admit was way above 175^oF), I strained it and allowed it to set overnight. Voila! Perfect custard, and no thermometers needed.


The Recipe. (Adapted from [2])

6 egg yolks
1 cup  plus 2 tablespoons powdered sugar
2 cups whole milk
2 teaspoons vanilla extract
1 (1/4oz) envelope gelatin
1/4 cup boiling water
1 1/2 cups 40% heavy whipping cream
1 teaspoon cornstarch

    In a large bowl, beat together egg yolks and powdered sugar until light yellow and fluffy. Bring milk and vanilla to a scald in a saucepan. Slowly add ladles of milk to the egg yolks, constantly stirring until all the milk is combined. Tempering the eggs like this prevents them from cooking up in lumps, and produces a silky texture. Stir the custard constantly over low heat with a spatula, carefully scraping the entire bottom of the saucepan to prevent it overcooking on the bottom. When the custard begins to coat the spatula and just begins to bubble, remove from heat.
    In a small bowl, stir gelatin into 1/4 cup boiling water until dissolved. Slowly add to warm custard while stirring. Strain custard through a wire mesh sieve into a bowl, cover surface with waxed paper, and chill overnight.
    The next day, make the stabilized whipped cream. Chill a large metal bowl and beater blades in the freezer for 10 minutes. Add some ice and water to a slightly larger bowl to create an ice bath, and set the chilled metal bowl inside it. Whip the cream on medium-high until soft peaks stand in the bowl. Add the cornstarch, and continue to beat on high until stiff peaks form. Be careful not to over-whip, as the cream will curdle.
    Before combining the custard and the cream, the custard must be whipped to make the texture more pliable so the whipped cream can be folded in. This can be done by either stirring with a whisk or beating it on low for a couple minutes. Fold the whipped cream into the custard, and stir until smooth. Store Bavarian cream in the refrigerator for up to 3 days.


1. Sawicki, Laura. "Cooking Basics-- How to Make Custard." Edible Austin. Available here.

2. Recipe by Nadia Hassani, in Spoonfuls of Germany. Available here.

Blooming Rose Cupcakes

The Art.
     So many cupcake toppers include rose decorations, but they usually require advanced skills with buttercream or fondant. I love this decorating technique because it is so stunning, yet doesn't require much decorating skill or special tools. In addition, covering a cupcake in real rose petals gives it an ethereal and romantic quality that simply can't be matched. While newbies can use this decorating technique, making the sugared rose petals will take some time and patience. In the end, you'll find it's worth it.
    I completed the rose theme with rose-flavored angelfood cake, topped with a billowy meringue icing.  The delicate texture and airiness of these cupcakes perfectly compliments the rose flavor. For presentation, I made a bouquet from the leftover flowers and wove ribbons around the plates.

The Science.

Structure of beta-Damascenone

    Rose scent is the most highly coveted floral scent in the perfume industry. The fragrance is exceedingly complex, varying from plant to plant and from season to season. Rose petals produce scent by releasing volatile compounds, which are made up of various terpenoids, phenylpropanoids, and fatty acid derivatives [1,2]. These compounds evaporate into the air and insects are drawn to the blooms, thus increasing the plant's pollination. Beta-Damascenone is an aromatic compound named after Rosa Damascena, and is the most common additive for rose flavor and fragrance. Through genetic manipulation, scientists have discovered several genes expressed in rose petals that are responsible for producing fragrance, exposing a link between bloom pigmentation and increased scent [2]. Sadly, most roses sold for floral arrangements have been bred for bloom color and size, and usually have little fragrance.

The Recipe.

Sugared Rose Petals:
One dozen organic roses in desired color
1 egg white
1 cup sugar

     Make sure your roses are grown organically and are not coated with anti-fungals after harvest. Gently pluck petals from 6 roses, discarding any browned or disfigured petals.  Rinse with water and pat dry. 

    Using a paintbrush, paint a thin layer of egg white on each petal, then dust with sugar, knocking off the excess.  Place on paper towels and allow to dry 1-2 hours. Store in the refrigerator in a single layer, and use petals within 24 hours.

Rose-flavored Angelfood Cupcakes:
1/3 cup cake flour
1/2 cup sugar
5 large egg whites*
1/4 teaspoon salt
1/2 teaspoon cream of tartar
1-2 teaspoons rosewater




    Preheat oven to 300^oF. Line a cupcake tin with paper liners. Sift flour twice, then sift together with 1/4 cup sugar. Sifting several times aerates the flour so the cake will be lighter. In a large bowl, beat egg whites on medium-high speed until frothy. Add salt and cream of tartar and beat until peaks barely form. Gradually beat in remaining 1/4 cup sugar and rosewater, mixing until soft peaks form. Gently fold in a third of the flour/sugar at a time, stirring until incorporated after each addition. Fill cupcake tin to the top with batter. Lift and drop the pans onto the counter a couple times to release air bubbles. Bake on center rack until tops are springy and toothpick inserted in center comes out clean, about 25  minutes.** Cool 10 minutes, then transfer to cooling rack until room temperature. Can be stored in an air-tight container in the freezer for two weeks. Yields 12 cupcakes.
*Save all of your egg yolks for the Bavarian cream recipe I'll give you later.
**If you have raucous children, pets, or significant others, tie them to a tree outside while the angelfood bakes.  The air in the beaten egg whites is what makes angelfood rise, so loud clatters will cause the cake to fall. Also, don't slam the oven door or bang pans around. Then you'll have no one to blame but yourself when your cupcakes fall, and you will have tied your loved ones to a tree for nothing (an act that is much easier to explain to social services while they're eating a fluffy cupcake).

Seven-Minute Meringue Icing:
1/2 cup sugar
3 tablespoons water
1 large egg white
1/8 teaspoon cream of tartar
Pinch of salt
1/2 teaspoon rosewater

    Bring one inch of water to a simmer in a medium saucepan.  Combine all ingredients in a large metal bowl, then set over saucepan to create a makeshift double-boiler.  Blend on high speed until soft peaks form, about 5 minutes. Wear an oven mitt on your hand that is stabilizing the bowl, to protect it from the steam. Remove from heat, add rosewater. Beat until icing is cool and billowy with stiff peaks, about 2 minutes.

Assembly:
    Frost cupcakes with a generous dollop of meringue icing and spread with spatula. Begin inserting rose petals into the icing around the edge of the cupcake. Work inward in a spiral until you reach the center.

I found that inserting 5 large petals on the periphery and 3-4 smaller ones in the center looked nice. Altering the angle at which you insert the petals will determine whether the cupcake looks more like a rosebud or a fully bloomed rose. Cupcakes can be stored in the refrigerator one day.

1. Flament, I. et al. "Volatile constituents of roses: characterization of cultivars based on the headspace analysis of living flower emissions. In: Teranishi R, Buttery RG, Sugisawa H (eds) Bioactive volatile compounds from plants." American Chemical Society (1993): 269-281.
2. Yan, Huijun et al. "Isolation and identification of a putative scent-related gene RhMYB1 from rose." Molecular Biology Reports 38.7 (2011): 4475-82.

Mustache-querade Cupcakes

The Art.
    It is Labmate George's birthday this week, and I wanted to make him extra special cupcakes. He requested a simple yellow cake with chocolate frosting, but this wasn't fancy enough for me. So, I sat down and asked myself, what kind of cupcake toppers would he like? Labmate George is a Hipster of the Hippest Sort, and trying to come up with an idea that he would consider "cool" made me feel painfully mainstream and frankly a little depressed. Finally, I was struck with an idea that I believe is utter brilliance: chocolate mustaches on a stick! I love the idea of all my labmates holding up edible Hercules Poirot mustaches to their faces. Hilarity is bound to ensue.

The Science.
    All jokes aside, it is very important for every baker to know that all chocolates are not created equal. This goes double for candymaking. Every type and brand of chocolate has a different ratio of cocoa solids, cocoa butter, milk fat, and milk [1]. Altering the ratios of these ingredients changes the melting temperature of the chocolate, and the texture it will have when it cools again. Dark and bittersweet chocolates have a high amount of cocoa solids and no milk, so they are harder at room temperature than milk chocolate. Baking bars are preferable to candy bars when melting, because they contain less sugar and fat and will create a nice hard confection.

    Another factor that must be considered are emulsifiers. These are fatty compounds, such as soy lecithin, that are added to chocolate to keep the fats from separating from the cocoa solids. Chocolate chips have more emulsifiers than bar chocolate, improving their texture and preventing the chips from sticking together. However, this also makes them undesirable for candymaking because the high fatty content inhibits the chocolate from hardening effectively. Inexpensive bar chocolates also contain more emulsifiers than pricier bar chocolate, because it allows the manufacturer to use less cacao [1]. If you take any of my advice from this blog post, please please please buy a good-quality, 60% cacao baking bar for your candymaking. NOT chocolate chips. Thank you.

The Recipe.

Yellow Cake:
2 1/4 cups cake flour
2 1/4 teaspoons baking powder
1/4 teaspoon salt
3/4 cup salted butter
1 1/2 cups sugar
4 eggs
1 1/2 teaspoons vanilla
1 cup buttermilk

    Preheat oven to 350^oF and line two cupcake tins with paper liners. In a medium bowl, comine flour, baking powder, and salt. Beat butter in large bowl on medium-high until fluffy, then gradually beat in sugar. Beat eggs in, one at a time. Stir vanilla into buttermilk. Alternately add flour mixture and buttermilk to butter/sugar/egg mixture while beating on low speed.  Beat an additional 30 seconds.
    Using a 1/3 cup measure, fill cupcake tins with batter.  Filling with a measuring cup is an efficient way to ensure that all the cupcakes have the same amount of batter and will bake evenly. Lift and drop the cupcake tins on the counter a couple times to eliminate bubbles in the batter. Bake on center rack for 20 minutes, or until a toothpick inserted into cake comes out clean. (Recipe modified from [2]).

Fluffy Chocolate Buttercream:
1 cup salted butter
1 cup vegetable shortening
1 cup cocoa
4-6 cups powdered sugar

    In a large bowl, beat together butter and shortening on medium speed until fluffy.  Beat in cocoa. Gradually beat in powdered sugar, until icing becomes thick enough for piping. I look for stiff, jagged peaks as my indicator. Adding the sugar in increments results in better incorporation into the butter, so you can use less sugar for the same consistency. If the frosting tastes too sweet and feels grainy, add a couple tablespoons of milk.

Mustache Toppers:
8 oz. Ghirhardelli 60% cacao bittersweet baking bar
25 pretzel sticks

   Place chocolate in a microwave-safe bowl and heat in microwave in 30 second increments, stirring inbetween, until only some solid chunks remain.  Let sit at room temperature 10 minutes, then stir.  Melting the chocolate in this way will ensure that you do not overheat and thicken it.
    Draw a mustache stencil on carstock paper and cut it out. Optimal size is 2-3" across. Use stencil to outline 24 mustaches on a sheet of waxed paper with permanent marker. Take care not to smudge the ink until it's dry.  I used a VWR indelible lab marker, because I'm a nerd. Turn the waxed paper ink-side down and place on top of cardboard or baking sheet.

    Spoon some melted chocolate into a resealable plastic sandwich bag, seal shut, and snip off the tiniest bit of the bottom corner to form a piping bag.  Pipe a chocolate border over your outlines on the waxed paper. Fill in with a zigzag motion, and smooth with a toothpick.  Mustaches should be thick, raised at least 1/4" above the surface of the waxed paper.  If they are too thin, go over them again with your piping bag. Place in refrigerator or freezer until hardened, about 20 minutes.
   To attach sticks to mustaches, dip the top 1/2" of a pretzel stick in melted chocolate, and press onto a cooled mustache, slightly to the side. Use a designated "gluing" pretzel to dab more chocolate around the pretzel stick to ensure that it is attached. Repeat with the remaining 23 mustaches. Eat your gluing pretzel, because it is delicious. Place mustaches in refrigerator until ready to top cupcakes.

Cupcake Assembly:
    Allow cupcakes and buttercream to reach room temperature. Using a piping bag and 1M tip, pipe a swirl on top of each cupcake as described in my previous tutorial. Stick a mustache topper into each cupcake and serve with a can of PBR, if desired.

1. Galvin, Lori et al. Test Kitchen Favorites. Brookline, MA: America's Test Kitchen, 2006.
2. Garrett, Toba. The Well-Decorated Cake. New York, NY: Sterling Publishing, 2004.