Beat butter and sugars at medium speed with an electric mixer until fluffy. Add eggs, 1 at a time, beating until blended after each addition. Add cooled chocolate and vanilla, beating until blended.
Combine flour and next 3 ingredients; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed after each addition. Pour batter into 2 greased parchment paper-lined 9" round cakepans.
Bake at 350° for 22 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks 10 minutes; remove from pans, and cool completely on wire racks.
Spread White Chocolate Frosting between layers and on top and sides of cake.
Let me offer a warning about the baking instructions this recipe called for! Two 9" cake pans are not big enough! When I made this, the batter overflowed into the oven and burned pretty badly. It also took well over 22 minutes to bake.
Eat Well. Lose Weight. Live Healthy. Delicious and healthy recipes customized for you!