Preheat oven to 400 degrees. Use a 13 x 9 inch cake pan.

2 c. flour
2 c. sugar
1/4 c. cocoa

Combine above in a bowl.

1 c. water
1 cube butter
1/2 c. oil

Combine in saucepan and bring to a boil, add to flour mix.

2 eggs
1/2 c. buttermilk
1 tsp. baking soda
1 tsp. vanilla

Combine and add to mixture. Grease and flour cake pan. Pour warm mixture in and bake 20 minutes.

ICING:

1 cube butter
1 box powdered sugar
1/3 c. milk
1/4 c. cocoa
1 tsp. vanilla
1 c. nuts (optional)

Heat and pour over warm cake.