Blend all ingredients except chocolate and beat with a mixer 4 minutes.
Pour all but 2 cups of batter into a greased 10-inch tube pan.
Stir chocolate into remaining batter.
Spoon chocolate batter into tube pan; marbelize by running a knife through the batters.
Bake for 45 minutes at 350Â° F.
Cool in pan for 10 minutes before removing to cool on rack.
Frost with Glossy Chocolate Frosting