Chocolate Buttermilk Sheet Cake

2 cups flour
2 cups granulated sugar
1/2 teaspoon salt
1/2 cup margarine
1 cup water
1/2 cup vegetable shortening
3 heaping tablespoons cocoa
2 eggs, beaten
1 teaspoon baking soda
1/2 cup buttermilk
1 teaspoon vanilla extract

Place in large mixing bowl, flour, sugar and salt. Place in saucepan margarine, water, vegetable, shortening and cocoa. Bring to boil and pour over flour mixture. Mix well. Place in another bowl eggs, baking soda, buttermilk and vanilla extract. Stir well and add to previous mixture. Bake in greased and floured 13 x 9-inch pan at 350 degrees F for 20 minutes.

Icing:
1/2 cup margarine
3 heaping tablespoons cocoa
1 (16 ounce) box confectioners' sugar
1 teaspoon vanilla extract
1/2 cup chopped nuts
6 tablespoons milk

Melt margarine and cocoa in a 2-quart pan, but do not boil. Remove from heat and add confectioners' sugar, vanilla extract, nuts and milk. Stir well. Ice cake while hot.