2 C sugar
2 C all-purpose flour
1/4 C cocoa
1/2 C (1 stick) margarine or butter
1 C water
1/2 C canola or vegetable oil
2 eggs
1/2 C buttermilk (milk to 2 tsp. vinegar)
1 1/2 tsp. baking soda
1 tsp. vanilla

Frosting:
16 oz. powdered sugar
1 C chopped nuts, toasted
1/4 C cocoa
1/2 C (1 stick) margarine or butter
1/3 buttermilk
1 tsp. vanilla

2 C sugar 2 C all-purpose flour 1/4 C cocoa 1/2 C (1 stick) margarine or butter 1 C water 1/2 C canola or vegetable oil 2 eggs 1/2 C buttermilk (milk to 2 tsp. vinegar) 1 1/2 tsp. baking soda 1 tsp vanilla 16 oz. powdered sugar 1 C chopped nuts, toasted 1/4 C cocoa 1/2 C (1 stick) margarine or butter 1/3 buttermilk 1 tsp vanilla

Preheat oven to 350.
Combine first three ingredients in a large bowl. Melt the butter with the water and oil in a small saucepan over medium-high heat, and bring to a boil. Pour this over the dry ingredients and mix well.
Add eggs, 1/2 C buttermilk, baking soda, and 1 tsp. vanilla and blend thoroughly.
Pour the mix into an 18x11 inch rectangular baking pan. Bake until a toothpick inserted in middle of the cake comes out clean, approximately 20-25 minutes.
While cake is baking, combine the powdered sugar, nuts, and remaining cocoa in a mixing bowl.
Remove the cake from the oven. Melt the remaining butter in a small saucepan over medium heat. Add to sugar mix with remaining buttermilk and vanilla, and blend thoroughly. Immediately pour this mix over the cake. Spread it evenly to the edges. Let the cake cool completely in the pan.