Chocolate Quark Cake

Directions

1. 1
   In a medium-size pan, heat the cream and sugar. Stir until the sugar has dissolved.
2. 2
   Add the chocolate & espresso powder and stir until it is thoroughly melted. Remove from the heat, cover, and let cool for about 10 minutes or at least to room temperature.
3. 3
   Using a mixer, mix the butter on medium-high speed until it is smooth and creamy.
4. 4
   Turn the mixer to medium-low and add half of the chocolate mixture along with the vanilla. Mix well. Add the remaining chocolate mixture and mix until smooth and creamy. Set aside until it hardens slightly, to become a spreadable consistency, 1 to 2 hours. (Or, you can refrigerate the frosting for about 30 minutes, or until it becomes thickened and spreadable. Bring it to room temperature before frosting.)
5. 5
   Preheat the oven to 350*
6. 6
   Generously grease three 9-inch round cake pans. Cut a piece of waxed paper to fit the bottom of each pan and place inside the pans. Grease the waxed paper, and dust the pans with cocoa powder until well coated. Set aside.
7. 7
   In a small heatproof bowl, pour the boiling water over the 1/2 cup cocoa. Stir until the mixture is very smooth, and set aside to cool.
8. 8
   Melt the chocolate in a double boiler. Stir occasionally until smooth. Remove from the heat.
9. 9
   Into a medium-size bowl, sift together both flours, the baking powder, and salt. Set aside.
10. 10
    In a bowl, beat the butter until smooth and creamy, (about 5 minutes). Add 2 1/4 cups of the sugar and beat until well blended, (about 5 minutes). Beat in the whole egg and egg yolks, one at a time. Beat in the cooled cocoa mixture until very smooth, scraping down the sides as you go. Turn the mixer to medium-low and add the melted chocolate, beating until well incorporated. Add the vanilla.
11. 11
    Turn the mixer to low and add half the dry ingredients. Then add the quark, mix well, and add the rest of the dry ingredients. Beat until smooth and creamy, 2 to 3 minutes.
12. 12
    In a bowl, using clean beaters, beat the egg whites at high speed. When frothy, add the remaining 1/4 cup sugar and continue beating until the egg whites form stiff peaks, 5 to 6 minutes.
13. 13
    Using a large rubber spatula, fold about 1 cup of the chocolate mixture into the egg whites. Then gently fold that mixture back into the chocolate mixture, just until the egg whites are well incorporated. Do not overmix.
14. 14
    Distribute the batter evenly among the pans, and bake in the center of the oven for 20 to 25 minutes. Do not overbake.
15. 15
    Cakes are done when the tops are just beginning to crack and a toothpick inserted into the center comes out with a few crumbs clinging to it. Let cool on a rack for about 15 minutes. Remove the cakes from the pans and let cool completely on a wire rack.
16. 16
    To assemble:
17. 17
    Place the first layer on a serving plate and frost the top only. Place the second layer on top of the first and frost the top. Repeat with the top layer. Spread the remaining frosting along the sides until the cake is completely covered with frosting.