Cake:

1 c. Coke
1/2 c. butter
1/2 c. oil
3 tbsp. cocoa
2 c. sugar
2 c. flour
1 tsp. baking soda
1/2 c. buttermilk
2 eggs
2 tsp. vanilla
1 1/2 c. miniature marshmallows

Frosting:

1/2 c. butter
3 tbsp. cocoa
6 tbsp. Coke
1 lb. confectioners sugar
1 tsp. vanilla
1 c. chopped walnuts

To make cake, bring first 4 ingredients to a boil. Combine remaining cake ingredients. Pour in Coke mixture and mix well. Pour into a greased and floured 13x9 inch pan. Bake at 350 degrees for 40 to 45 minutes.

To make frosting, bring first 3 ingredients to a boil. Combine remaining ingredients. Pour in butter mixture and mix well. Spread on hot cake.