Frost it with Chocolate Frosting for a chocolate-lover's birthday cake. Yum!
Grease 2 9" pans, dust with flour.
Combine chocolate, 1/2 c sugar, 1 c milk. Cook, stirring constantly, until mixture thickens and turns a deep chocolate color. Cool.
Stir vinegar into the remaining 1/2 c. milk. Let stand. The vinegar will curdle the milk. This is okay. You can use 1/2 c. buttermilk instead if you've got it.
Sift dry ingredients: cake flour, baking soda, baking powder, salt.
Beat butter, sugar, yolks on high, 3 minutes. Beat in chocolate mixture until light and fluffy. Stir in flour, alternating with curdled milk.
Beat whites until stiff but not dry. Fold in.
Bake at 350°F for 30 minutes. Cool for 10 minutes in pan. Turn out of pans, allow to cool completely on racks.
Frost when cool, share and enjoy.