20 September 2013

Teatime Tiramisu

 The Art.
    One of the reasons I will never be a real adult is because I don't drink coffee. I assume that real grown-ups stand around in suits, slurping coffee and talking about portfolios and stuff. The best I can do in that regard is sit around in my jeans with a cup of tea and talk about Science. However, while adulthood continues to evade my grasp, I do consider myself a professional tea drinker. When I brew  a cup it is a delicate process that involves loose-leaf tea, thermometers, timers and different protocols for each one to produce a perfect tea that is flavorful, but not bitter. 
    It is my love for tea that inspired me to make this Teatime Tiramisu. By replacing the espresso with English Breakfast tea, the flavor of the cake becomes lighter and smoother, but no less complex. Adding lemon to the cream makes the cake reminiscent of a cup of tea with a twist of lemon. The brandy and Riesling also give it a hint of alcohol, which combines with the black tea and lemon to create a very unique flavor that is earthy, tart, and delicately sweet. This cake can be served at teatime with a pot of tea, or after dinner with the remaining Riesling (assuming you didn't drink it all while the cake was chilling).

The Science.
    English Breakfast is a black tea, which means that it is made from tea leaves that have been withered and fermented. Depending on what region the tea leaves are grown in and how they are treated, black teas can have a variety of different flavors and aromas. The compounds that give tea its aroma are broadly classified as phenols and flavonoids. A Japanese research group has determined that the "sweet" flavors in some more full-bodied black teas are imparted by epoxydecenals that are produced by the fermentation process, and are not found in green tea [1]. Moreover, another group has found that length of brewing time and addition of milk can affect how much of these aromatic compounds our bodies absorb from drinking tea [2]. This, in turn, may affect how well the tea we drink will provide health benefits, such as prevention of diabetes and cancer [2]. For the highest concentration of antioxidant compounds, the group recommends steeping black tea for 7 minutes, however I have always found that it is less bitter with a 5 minute brew time. I suppose you'll just have to choose whether you want a smooth cup of tea or more antioxidants.

The Recipe.

Syrup:
2 cups boiling-hot water
5 English Breakfast teabags
3 tablespoons sugar
3 tablespoons brandy

Cake:
juice from 2 lemons
1 teaspoon gelatin
4 egg yolks
1/3 cup Riesling
1/2 cup sugar
1 pound mascarpone
1 cup 40% heavy cream
1 tablespoon lemon zest
36 biscotti savoiardi (lady fingers)

    Steep tea in hot water for 10 minutes. Add sugar and brandy and stir until dissolved, then set aside.  Sprinkle gelatin over the lemon juice and allow to bloom for 5 minutes in a large bowl. Be sure to use a glass bowl, because a metal one will give the lemon juice a metallic taste. Meanwhile, set a saucepan with 1 inch of water on the stovetop to simmer. Once the gelatin is bloomed, add the egg yolks, Riesling, and sugar, then set over the saucepan to make a double boiler. Beat the mixture on medium speed while it heats for 5 minutes, until it is frothy and tripled in size. Remove from heat and fold in the mascarpone, then place in the fridge. 
 
    To whip the cream, prechill a metal bowl and beaters in the freezer for 10 minutes. Place the bowl over an ice bath and whip the cream on medium speed until stiff peaks form. Be careful not to over-whip and curdle the cream. Fold the whipped cream and the lemon zest into the mascarpone mixture.
    Assemble the cake by dipping the savoiardi in the tea syrup, then layering them in the bottom of a 9x13 glass dish. Cover with 1/2 of the cream mixture. Add another layer of soaked cookies, then top with the rest of the cream. Refrigerate for at least 4 hours before serving. 
     For a beautiful garnish, you can make lemon peel curls as I instructed in the Orange Gingerbread Bundt Cake post. They're a very easy way to dress up this beautiful dessert!
1. Kumazawa, K. et al. "Characterization of Epoxydecenal Isomers as Potent Odorants in Black Tea (Dimbula) Infusion." Journ. of Agri. and Food Chem., 2006. Vol. 54 (13), pp 4795–4801.
2. Kyle, J. et al. "Effects of Infusion Time and Addition of Milk on Content and Absorption of Polyphenols from Black Tea." Journ. of Agri. and Food Chem., 2007. Vol 55 (12), pp 4889–4894.


05 September 2013

Raspberry Cobbler


The Art.
    My sister is in college, and she recently complained to me that all the recipes I post are too complicated for her to make. I feel kind of bad about that, so this post is dedicated to my sister, and all the other college students who would like to take a stab at baking. Thinking back to my college days, I realized that this meant I needed to make a recipe that was idiot-proof and didn't require a mixer. With this goal in mind, I created something affordable, easy, and (most importantly) delicious. Since raspberries are in season right now, you can probably get them very cheap--I got mine for $1 a carton. If fresh berries are out of your budget, frozen ones will do just fine. This recipe also only requires 10 minutes of active time, so you can cram 30 minutes of studying in while it bakes. Nothing motivates a good study session like the reward of raspberry cobbler!

The Science.
    Since raspberries have a high water content, the filling in this recipe calls for tapioca. I have to admit, before I made my first fruit dessert I thought tapioca was just a type of pudding. In reality, tapioca is a starchy root that is derived from the cassava plant, and is used as a thickening agent in baked goods. Tapioca is ideal for thickening because it is a type 3 starch, which means it has long chains of sugars that intertwine with each other when they are heated [1]. This interaction between the sugar chains gives tapioca its gelatinous properties. In fact, the cassava plants that we harvest tapioca from today contain very high levels of the enzymes that produce starches, called starch synthases. This is partly due to human selection as we domesticated the plant, but also because of a natural mutation that occurred evolutionarily in cassava, duplicating the gene that encodes starch synthase [2].

 

The Recipe.

Filling:
24oz fresh raspberries
2 tablespoons sugar
1 teaspoon tapioca

Crust:
1 cup flour
1/2 cup sugar
1 teaspoon baking powder
6 tablespoons butter, cut into pieces
1/4 cup buttermilk
zest from 1 lemon

      Preaheat oven to 425°F. Mix filling ingredients and pour into an 8x6in. or 8x8in. glass dish, then set aside. In a medium bowl, combine flour and sugar. Add butter, and crumble with fingers until the mixture is uniform and similar to cornmeal. Stir in buttermilk and lemon zest. Drop dough by spoonfuls over the raspberry mixture, and bake on center rack for 30 minutes, until crust is golden brown. Allow to cool 10 minutes before serving. 

1. Vamadevan, V et al. "Impact on molecular organization of amylopectin in starch granules upon annealing." Carbohydr. Polym, 2013. Vol. 98 (1), pp1045-55.
2.  Yang, Z et al. "Molecular evolution and functional divergence of soluble starch synthase genes in cassava (manihot esculenta crantz)." Evol. Bioinform. Online, 2013. Vol. 9, pp239-49.