This is a fabulous cake. It’s light and yet still richly chocolatey.

4 oz bittersweet chocolate, finely chopped
1/2 c sour cream or yogurt
1 c brown sugar
2 c flour
a bit of salt
3 tbsp unsweetened cocoa
1 tsp baking soda
1 stick unsalted butter, at room temperature
1 c white sugar
2 eggs, separated
1 tsp vanilla
3/4 c water, at room temperature

3 8″ cake pans, or 2 9″ cake pans, buttered and the bottoms lined with parchment

Put the chopped chocolate, sour cream and brown sugar into a heavy saucepan and set over very low heat. Stir occasionally until melted and smooth. Remove from the heat and set aside.

Sift the flour, salt, cocoa, and baking soda onto a sheet of wax paper and set aside.

Put the butter into a bowl and beat until creamy. Gradually beat in the white sugar. Beat in the egg yolks, one at a time, followed by the vanilla. Mix in the flour mixture, 1 tbsp at a time, alternately with the water. When thoroughly blended, work in the melted chocolate mixture.

In a separate bowl, beat the egg whites until stiff, then gently fold into the batter.

Spoon the batter into the prepared cake pans, then bake at 350 for 25 minutes (for 8″ cakes) or 30 minutes (for 9″ cakes). Let cool for 5 minutes, then invert on a wire rack, remove the parchment, and cool completely before frosting.

Tony used cream cheese frosting (because he knows how I feel about cream cheese frosting), but this is what the recipe calls for, which sounds pretty good, too:

Frosting & Filling
5 oz bittersweet chocolate, finely chopped
5 oz milk chocolate, finely chopped
1 c sour cream

Melt chocolates together in top of a double boiler or in the microwave, then beat in the sour cream. Leave until very thick and spreadable.