2 sticks butter
3 c. sugar
5 eggs (or 4 lg. eggs)
1/2 c. vegetable oil
3 c. all-purpose flour
1 c. milk
1/2 tsp. vanilla
4 heaping tbsp. cocoa

Cream butter and sugar until light and fluffy. Add eggs; beat after each. Blend in oil and add flour alternately with milk, beginning and ending with flour. Add vanilla. Separate batter into 2 bowls. Blend cocoa into 1 bowl of the batter. Pour plain batter into a 10 inch greased and floured tube pan. Spread cocoa batter over top and swirl in with a knife to make a marble effect. Bake at 325 degrees for 1 hour and 30 minutes or until a toothpick inserted in center comes clean.