Adapted from Smitten Kitchen
2 ounces chocolate
1 cup coffee
2 cups sugar
1 2/3 cup flour
1 cup cocoa
1 1/3 teaspoons baking soda
1/2 teaspoon baking powder
1 teaspoon salt
1/2 cup oil
1 cup buttermilk
1/2 teaspoon vanilla, etc. and reduce the baking time by at least ten minutes.
Preheat oven to 300°F. and grease pans. Line bottoms of 2 9-inch round cake pans with wax paper and grease paper.
Finely chop chocolate and in a bowl combine with hot coffee. Let mixture stand, stirring occasionally, until chocolate is melted and mixture is smooth.
Into a large bowl sift together sugar, flour, cocoa powder, baking soda, baking powder, and salt. In another large bowl with an electric mixer beat eggs until thickened slightly and lemon colored (about 3 minutes with a standing mixer or 5 minutes with a hand-held mixer). Slowly add oil, buttermilk, vanilla, and melted chocolate mixture to eggs, beating until combined well. Add sugar mixture and beat on medium speed until just combined well.
Divide batter between pans and bake in middle of oven until a tester inserted in center comes out clean, 50 minutes to one hour.
Cool layers completely in pans on racks. Run a thin knife around edges of pans and invert layers onto racks. Carefully remove wax paper and cool layers completely. Cake layers may be made 1 day ahead and kept, wrapped well in plastic wrap, at room temperature.
4 large egg whites
1 cup sugar
1/2 cup light corn syrup
4 tablespoons water
3 teaspoons pure vanilla extract
Combine frosting ingredients with a pinch of salt in a metal bowl set over a saucepan of simmering water and beat with a handheld electric mixer at high speed until frosting is thick and fluffy, 6 to 7 minutes. Remove bowl from heat and continue to beat until slightly cooled. Use frosting the day it is made.