1/2 c. oil
2 sticks butter
1 c. Coca-Cola
1/2 c. marshmallows
2 c. plain flour
1 tsp. baking soda
2 1/2 tbsp. cocoa
2 c. sugar
1/2 c. buttermilk
2 eggs
1 tsp. vanilla

Bring first 3 ingredients to a boil, set aside to cool. Mix rest of ingredients and mix all together. Bake in sheet pan or casserole for 45 minutes at 350 degrees.

ICING:

1 stick butter
1 box powdered sugar
6 tbsp. Cola
1 tsp. vanilla
2 1/2 tbsp. cocoa
1 c. chopped nuts

Bring to a boil and pour over cake.