Double Fudge Coca-Cola Cake

1 cup coca-cola
1/2 cup oil
1/2 cup margarine
3 tablespoons baking cocoa
2 cups granulated sugar
2 cups all-purpose flour
1/2 teaspoon salt
2 large eggs
1/2 cup buttermilk
1 teaspoon baking soda
1 teaspoon vanilla
FROSTING:
1/2 Cup margarine
3 tablespoons baking cooa
6 tablespoons cream or milk
1 teaspoon vanilla
1/2 cup pecans -- chopped
1 pound powdered sugar

For cake, in a saucepan bring cocoa-cola, oil, margarine and cocoa to a boil, mix the sugar, flour and salt. Pour in the boiling liquid and beat well. Add the eggs, buttermilk, soda, and vanilla and beat well. Pour into a greased and floured sheet cake pan, and bake at 350 degrees for 20-25 minutes.

For frosting, in a saucepan combine the butter, cocoa and milk and heat until the butter melts. Beat in the remaining ingredients, and spread on the hot cake. Cool completely before cutting.