Texas Sheet Cake

Ingredients
    •    2 cups all-purpose flour
    •    2 cups white sugar
    •    1 cup butter
    •    1 cup water
    •    1/2 cup shortening
    •    1/2 cup unsweetened cocoa powder
    •    1/2 cup buttermilk
    •    2 eggs
    •    1 teaspoon baking soda
    •    1 1/2 teaspoons vanilla extract
    •    6 tablespoons milk
    •    4 cups confectioners' sugar

Directions
    1.    Sift together and set aside in large bowl the flour and sugar.
    2.    In saucepan over medium heat bring to a boil; 1/2 cup margarine or butter, 1/2 cup shortening, 1 cup water, and 4 tablespoons cocoa.
    3.    Pour cocoa mixture over flour and sugar mixture. Stir in buttermilk, eggs, baking soda, and 1/2 teaspoon vanilla. Mix well and pour into a greased and floured sheet pan.
    4.    Bake in a preheated 400 degrees F (205 degrees C) oven for 20 minutes.
    5.    To Make Frosting: Five minutes before cake is done, bring to boil in a saucepan 1/2 cup margarine or butter, 6 tablespoons milk, and 4 tablespoons cocoa. Remove from heat and immediately stir in the confectioners' sugar, nuts (if desired), and 1/2 teaspoon vanilla extract. Beat until smooth and immediately pour frosting over cake. Cake may be served warm or at room temperature.