1/2 c. butter
2 c. flour
2 egg yolks
1 c. sugar
1 c. milk with 1 tbsp. vinegar
4 tbsp. cocoa
1 tsp. baking powder
1/4 tsp. salt
1 tsp. baking soda
1 tsp. vanilla

FILLING:

2 egg whites
3/4 c. Crisco
2 c. powdered sugar
1 tsp. vanilla

Mix all ingredients in a bowl and mix with an electric mixer. Drop by teaspoon onto cookie sheet (greased and floured) to make rounds. Bake at 350 degrees for 10 to 12 minutes. Beat filling hard and place between two cookies.