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.