Grandmother's Potato Cake

1 cup butter or maragine
2 cups sugar
2 eggs
1 cup cold mashed potatos
1 tsp. vanilla extract
2 cups all-purpose flour
1/4 cup baking cocoa
1 tsp. baking soda
1 cup milk
1 cup chopped nuts
In mixing bowl,cream butter and sugar until fluffy. Add eggs,one at a
time,beating well after each addition. Blend in potatoes and vanilla.
Combine flour,cocoa,and baking soda;add alternately with milk,blending
well after each addition. Stir in nuts. Pour into a greased 13-in. x
9-in.x 2-in. baking pan. Bake at 350 degrees for 40-45 minutes or until
cake tests done. Cool on a wire rack.