Samoa Sheet Cake

This is great for a large crowd. You can use a boxed chocolate cake mix if you desire.
 * 2 cups flour
 * 2 cups sugar
 * ½ cup butter
 * 1 cup water
 * 4 Tablespoons cocoa
 * ½ cup shortening
 * ½ cup buttermilk
 * ½ teaspoon baking soda
 * 2 eggs
 * 1 teaspoon vanilla

ADDITIONAL TOPPINGS
 * ½ cup butter
 * 6 Tablespoons milk
 * 3 cups powdered sugar
 * 1 teaspoon vanilla
 * ⅛ cup caramel sauce, I used caramel ice cream topping in the jar
 * 2½ cups toasted coconut, See instructions below for how to make it
 * 7 to 8 ounces caramel, either Kraft Caramel Cubes or from a block of Caramel. I used a block of Peter's Caramel.
 * ⅛ cup evaporated milk
 * ¾ cup milk chocolate chips
 * 1 teaspoon shortening or oil