Serves 10.

Note: From "Cooking for Mr. Latte" by Amanda Hesser (W.W. Norton). Substitute buttermilk for milk and cider vinegar. Cake doesn't need to be refrigerated, but it should be served within 24 hours if stored at room temperature. If refrigerated, serve chilled ("My mother kept it in the fridge, and it is sublime even when cold," wrote Hesser) or let sit at room temperature for an hour before serving. For bakers who prefer a lot of icing, use 2 cups chocolate chips and 2 cups sour cream.

For cake:

• 2 c. sugar

4 oz. unsweetened chocolate, chopped into pieces

1/2 c. (1 stick) unsalted butter, plus more for pan

• 2 c. flour, plus more for pan

• 2 tsp. baking soda

• 1 tsp. baking powder

• 1 tsp. sea salt

• 1 c. milk

• 1 tsp. cider vinegar

• 2 eggs

• 1 tsp. vanilla extract

For icing:

• 1 1/2 c. semisweet chocolate chips

1 1/2 c. sour cream, at room temperature


To prepare cake: Preheat oven to 375 degrees and place a baking sheet on the lowest rack to catch any drips when cake bakes. Grease and flour a 9-inch tube pan.

(Note: If you prefer, you can grease pan, line the bottom with parchment paper, then grease and flour pan. This is not necessary, but parchment paper does make getting the cake out easier. In place of a tube pan, divide the batter evenly between a pair of 9-inch round baking pans. Prepare the pans in the same way, using butter, flour and parchment paper. The baking time is shorter; start checking for doneness around 20 to 25 minutes. For cupcakes, pour batter into greased, lined muffin pans and bake for about 15 to 20 minutes. )

In a large saucepan over medium heat, combine sugar, unsweetened chocolate, butter and 1 cup water. Stir occasionally until all ingredients are melted and blended. Remove from heat and cool slightly, about 15 to 20 minutes.

Meanwhile, in a medium bowl, sift together flour, baking soda, baking powder and salt.

In a small bowl, stir together milk and vinegar.

When chocolate mixture has cooled a bit, whisk in milk and eggs until thoroughly combined. In several additions (and without overmixing), whisk in the flour mixture. When batter is smooth, add vanilla extract and whisk once or twice, to blend.

Dump batter into prepared tube pan and bake on the middle rack until a skewer inserted into the center comes out clean, about 30 to 35 minutes.

Remove pan from oven, transfer pan to a wire rack and cool cake for 10 minutes. Place a ring of wax paper on top of the cake so you have something to grab onto when turning it out, then remove cake from pan (this can be tricky, so if someone is around, enlist their help). Cool cake completely on wire rack.

To prepare icing: In a double boiler over gently simmering water, melt chocolate chips. Remove from heat and let melted chocolate cool to room temperature.

It is very important that the melted chocolate and the sour cream be the same temperature, otherwise the icing will be lumpy and grainy (test it by stirring a little of the sour cream and chocolate together in a small bowl; if it mixes smoothly, it's ready).

Stir in sour cream, 1/4 cup at a time, until icing is smooth. When cake is cool, cut it into two layers. Lay the top layer, top-side-down, onto a cake plate or serving platter. Spread top with icing. Top with bottom layer, setting it bottom-side up; this will create a straighter edge. Spread remaining icing evenly over top and sides.