Chocolate Cake Directions

Set a rack in the middle of the oven and preheat to 350°F. Butter two 9-inch cake pans with 1 3/4-inch sides. Line the bottom of the pans with parchment paper and dust the sides with cocoa powder, tapping out excess. Set aside.

In the bowl of a stand mixer using the paddle attachment mix together the cocoa powder, baking powder and baking soda, sugar, flour, salt, and espresso powder.

In a 2 cup glass measuring cup add the buttermilk, vegetable oil, and vanilla extract. Using a fork, beat the eggs into the buttermilk mixture.

Add the buttermilk mixture to the flour mixture and beat on medium speed for 2 minutes. Pour in boiling water and beat for an additional minute. (The batter will be thin.) Be sure to check that the batter at the bottom of the bowl is fully incorporated.

Divide the batter evenly between the two prepared pans. Bake until a toothpick inserted into centers comes out clean, about 30-35 minutes. Cool cakes in pans on racks about 10 minutes. Turn out onto racks and cool completely prior to frosting the cake.

Chocolate Mascarpone Frosting Directions

Place the egg yolks and salt in the bowl of a stand mixer and using the whisk attachment whip them until pale yellow in color.  While the yolks are whipping, in a small pan heat sugar and corn syrup; stirring with a heat-proof spatula to dissolve the sugar.  Once the sugar is dissolved stop stirring and allow the syrup to come to a full boil (meaning large bubbles are covering the entire surface of the syrup).

After the eggs are whipped stop the machine and pour a small amount of the hot sugar syrup into the eggs.  Quickly whip the mixture. Continue stopping the machine, pour in another tablespoon and whip. As the eggs heat up (test by touching the outside of the bowl with your hand) you can add more at a time. I found that by stopping the machine each time less sugar syrup gets spun onto the inside bowl.

When all the sugar syrup has been added, increase speed to medium-high and whip the egg/sugar mixture until the bowl is cool to the touch. Reduce the mixer speed to medium and add a couple of tablespoons of butter at a time incorporating each before adding the next one. After all the butter has been incorporated, add the chocolate (and mascarpone, if using.) Return the mixture to medium-high and whip until the buttercream is fluffy, a couple of minutes.  Frost the cake and serve.

*Variation: Reduce the butter to  1 3/4 cups (12 oz/337.5 g) and increase the mascarpone to 1 cup (8 oz/230 g). Continue the recipe as above.