Deep, dark and totally chocolaty, just call this cake pure comfort food. The smooth, shiny ganache that frosts the cake is easily made with just two ingredients�semisweet chocolate and whipping cream.
1. Preheat oven to 350F. Grease and flour two 9 x 2-inch round cake pans. In a saucepan, melt butter and unsweetened chocolate, stirring, over low heat. Set aside; cool slightly.
2. Combine flour, sugar, cocoa, baking soda and salt in a large bowl of electric mixer. Add chocolate mixture, buttermilk and eggs. Beat at low speed for 1 minute; increase speed to high and beat until light and fluffy, about 2 minutes.
3. Divide batter equally between prepared pans. Bake until cakes spring back when gently pressed, 35�40 minutes. Cool in pans 5 minutes; invert onto wire racks.
4. Bring cream just to a boil. Remove from heat and stir in chocolate chips; mix until frosting is smooth and starts to thicken.
5. Place 1 cooled layer on a cake plate. Spread top with 1/3 cup frosting. Top with second layer. Frost top and side of cake with remaining frosting.