PREAHEAT oven to 350°F. Butter and lightly flour two 9-inch layer pans.
SIFT Swans Down Cake Flour once, measure, add baking powder, salt and sugar and sift once more.
IN a large bowl stir butter to soften; add dry ingredients, ¾ cup of the milk, and the vanilla.
MIX on low speed until moistened. Beat on low speed 2 minutes. Add eggs and remaining milk; beat 1 minute longer.
POUR batter into prepared pans. Bake about 20-25 minutes; until tester inserted in center comes out clean. Cool in pans 10 minutes. Remove from pans and cool completely on wire racks.
FROST with Chocolate Butter Frosting.
CREAM butter and 2 cups sugar in small bowl. Beat in vanilla and melted chocolate.
ADD remaining sugar gradually, beating well after each addition.
THIN with milk to reach desired consistency.