1. Preheat oven to 350 degrees.
2. Cream butter and sugar together thoroughly. Add beaten eggs.
3. In a separate bowl, sift dry ingredients together.
4. Combine milk and vanilla in a small bowl.
5. Alternately add milk mixture and sifted dry ingredients to creamed mixture. Beat for two minutes. Add melted chocolate and blend until evenly distributed.
6. Pour into two greased 9-inch cake pans. Bake for 40 to 45 minutes.
Frost with Buttercream Frosting.