1. Mix together all ingredients, except chocolate, until creamy. Pour three-fourths of batter into greased Bundt pan.
2. Melt chocolate and mix into remaining batter.
3. Pour this chocolate mixture onto the cake and marbleize by running a long knife zigzag through the chocolate and the batter underneath.
4. Bake for one hour. Don’t overbake!
5. Preheat oven to 350 degrees Fahrenheit.