Cake:

1/4 cup buttermilk
1/4 cup cocoa
2 eggs, beaten
1 cup water
1 cup butter
2 cups sugar
2 cups flour
1 teaspoon baking soda
1 teaspoon vanilla

Mix together 1/4 cup buttermilk, 1/4 cup cocoa, eggs, water and 1 cup butter. Add in sugar, flour, baking soda and vanilla. Beat until smooth.

Grease and flour a 9x13-inch baking pan. Bake at 350°F for 25 minutes. Let cool.

Peanut Butter Layer:

1 cup peanut butter
1 tablespoon salad oil

Mix together peanut butter and salad oil. Spread over cooled cake. Refrigerate for 20 minutes.

Frosting:

1/4 cup cocoa
1/2 cup butter
1 (1 lb.) box powdered sugar
6 tablespoons buttermilk
1 teaspoon vanilla

Heat 1/4 cup cocoa and 1/2 cup butter. Stir until it bubbles. Add powdered sugar, 6 tablespoons buttermilk and vanilla. Beat until smooth and spread over cake.