Grease and flour two 9-inch round cake pans.In a large mixing bowl, beat the butter and brown sugar until creamy.Add the eggs, one at a time, and the buttermilk, beating continuously.
In a separate bowl, sift together the flour, cocoa powder, baking soda and salt.A cup at a time, add the flour mixture to the creamed mixture, beating after each addition.Pour half the mixture into each pan.Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Cool for 10 minutes and then turn the cake layers onto a cooling rack.Cool completely before frosting.
Makes 12 servings
Chocolate Buttercream Frosting
2 sticks (1 cup) butter, softened
1/3 cup whipping cream
1 ½ t. pure vanilla extract
1 cup cocoa powder
4 cups powdered sugar, sifted
In a mixing bowl, beat the butter until creamy.Add the cream and vanilla. Beat until smooth.Mix in the cocoa powder.Gradually add the powdered sugar, beating continuously until smooth and spreadable.