Chocolate Layer Cake

Make cake: Preheat oven to 350 degrees. Butter two 8-inch round cake pans. Line bottom of pans with parchmentpaper rounds; butter parchment. Set pans aside.

Heat butter and chocolate in a bowl set over (not in) a pan of simmering water, stirring occasionally, until almost melted. Remove from heat; stir until completely melted.

In a medium bowl, whisk together granulated sugar, flour, baking soda, and salt. In a large bowl, combine sour cream and eggs; whisk in coffee. Gradually add dry ingredients then chocolate mixture, stirring until just combined. Divide batter equally among prepared pans.

Place pans on same rack in oven; bake, rotating pans halfway through, until a toothpick inserted in the center comes out with a few moist crumbs attached, 30 to 35 minutes. Cool in pans 10 minutes; run a knife along edge of cakes, then invert onto a wire rack to cool completely before frosting.

Make frosting: Heat chocolate and butter in a mixer bowl set over (not in) a pan of simmering water, stirring occasionally, until almost melted. Remove from heat; stir until completely melted.

With mixer on low speed, add vanilla and salt. Gradually add confectioners' sugar and milk in alternating batches; beat until smooth. Let stand 5 minutes.

To frost cake, place a cake layer bottom side up, on a serving plate (tuck strips of waxed or parchment paper under edge of cake), spread about 3/4 cup frosting over the top. Place the other cake layer on top; cover assembled cake with remaining frosting.