Use Duncan Hines Fudge Marble Cake mix. Add nuts.

ICING:

1 stick pure butter
1 (8 oz.) carton Philadelphia cream cheese
3/4 carton white confectioners' sugar
1/2 carton sour cream
1/2 tsp. vanilla flavor
Nuts (pecans), toasted, as much as desired

Mix together by hand, do not use blender. If too thick add a small amount of Pet milk. (The more you mix, the creamier it becomes.)