Nancy's Black Cake

Thanks to Aunt Nancy for this recipe!  I sure hope at some point you decided to share it with your sister!! 
I am not usually a big fan of chocolate cake--it's typically too dry for me, but this cake is moist, easy and awesomely chocolately!  This is maybe the simplest "scratch" cake I've ever made. 

Butter a 9" x 13" pan, then sprinkle cocoa powder like you would flour, coat the pan and pour out the excess.  In a large mixing bowl, mix all the following ingredients well.

1 cup brown sugar
1/2 cup shortening
1 t. vanilla
2 squares (2 oz) baking chocolate, melted
1/2 cup milk + 1 t. vinegar
1 cup boiling water + 1 t. baking soda
1 cup white sugar
2 eggs
2 cups flour
3/4 t. salt

Pour into the prepared pan and bake at 350 degrees for 30 minutes.

Frosting

Melt together:
5 T. sugar
2 T. butter
3 T. evaporated milk

Bring to boil, then remove from stove and add 1/2 cup chocolate chips.  Beat till smooth and pour over hot cake.