German Chocolate Sheet Cake

For as long as I can remember, German chocolate sheet cake has been a family favorite dessert. Every family member has a recipe box that carefully contains my grandmother's renowned recipe, which my dad asks for on his birthday. I never gave much thought to the notion that German Chocolate Cake was, well, German, since my dad's side of the family is really German. You can thus imagine how shocked I was to find it was untrue!

Two cups of all-purpose flour
1/2 cup chocolate powder and 2 cups white sugar
One cup water, one stick of butter, one-half cup shortening
German baking chocolate, 4 oz.
Half a cup of buttermilk
One tsp baking soda
Half a teaspoon of salt
two eggs
One tsp vanilla
Can of 12-ounce evaporated milk
three yolks from eggs
Half a cup of butter
One cup of sugar
Half a cup of brown sugar
a half-cup of grated coconut
1 ½ cups finely chopped pecans
A quarter-tsp vanilla