This was the default chocolate birthday cake for our family.
Beat eggs with buttermilk and add vanilla. Sift dry ingredients and add to egg mixture, then add butter and chocolate which have been melted together in double boiler. Beat thoroughly. Pour into 2 greased 8-inch cake pans and bake about an hour at 325º. Original recipe said 30 minutes at 350º. I changed it. The edges were getting done before the middle.
I usually use mocha frosting for this cake:
2 cubes butter softened
1 - 1 1/2 boxes powdered sugar
1/2 - 3/4 cups cocoa powder
1 tablespoon instant coffee dissolved in about 1 tablespoon hot water
1 tablespoon vanilla
Add cream if it seems too thick.
Substitute for buttermilk:
1 1/2 cup sour cream
1 /2 cup milk