Heath Bar Cake - cooking recipe

Ingredients

1 pkg. Duncan Hines marble cake mix (reserve chocolate mix)
1/2 to 3/4 c. buttermilk
1/2 c. oil
4 eggs
1 pkg. instant vanilla pudding

Preparation

Mix well (beat quite a while), then pour into 3 round cake pans.
Swirl in some chocolate mixture in each pan.
Bake at 350\u00b0 until done.
Cool.