1/2 c. shortening
1 c. sugar
2 egg yolks (save whites)
2 c. flour
5 tbsp. cocoa
1 tsp. baking powder
1 tsp. baking soda
1/2 tsp. salt
1 c. milk
1 tbsp. vinegar (to sour milk)
1 tsp. vanilla

FILLING:

3/4 c. marshmallow fluff
1/2 c. butter
2 c. confectioners' sugar
1 tsp. vanilla
2 egg whites

Cream shortening and sugar, add egg yolks and blend well. Sift dry ingredients with flour. Add milk and vanilla. Mix all ingredients together blending well. Spoon by small amounts onto a well greased cookie sheet. Bake at 325 for 12-15 minutes. After cookies have cooled, spread filling on flat side of cookie and top with flat side of another.

FILLING: Mix all ingredients together; blend well.