chocolate whoopie pies

Chocolate Whoopie pies
cream together thoroughly
1 1/2 c soft butter
3 cups sugar
Add, beating until fluffy
3 eggs
2 tsp vanilla
Sift together dry ingredients
5 1/2 c flour
1 1/2 tsp baking soda
1 1/2 tsp salt
2/3 c cocoa powder
Make sour milk
2 1/4 c thick sour milk or buttermilk—how do you make sour milk? In a measuring cup add 2 and almost 1/4 c milk. Add 2 T of vinegar to the milk and then stir, instant sour milk.
Add sifted dry ingredients alternately with milk. Chill dough at least 1 hour. Drop onto greased baking sheet. Bake at 350 for 8-10 minutes.

Filling:
5 T flour
1 c milk
Mix together in a saucepan and cook until thickened, stirring constantly. Mixture will be very thick. Cool thoroughly.

1 c shortening
1 c sugar
1/2 tsp vanilla
Beat together. Then add flour mixture and beat until very fluffy about 5 minutes.
Spread on cooled cookie and press two together. You can wrap these individually and freeze them.