1 stick butter, softened
1 c. sugar
1 egg yolk
1/2 c. cocoa
2 c. flour
1 tsp. baking soda
1/2 tsp. baking powder
1/2 tsp. salt
1/2 c. milk
1 tbsp. vinegar
1/2 c. hot water

FILLING:

1 egg white
1 tsp. vanilla
1 tbsp. flour
1 1/2 tbsp. milk
1/2 c. Crisco
2 c. powdered sugar

Cream together butter, 1 cup sugar, and 1 egg yolk. Set aside. Sift together cocoa, flour, baking soda, baking powder, and salt. Add dry ingredients to creamed mixture alternately with milk mixed with vinegar. Add hot water. Drop by teaspoonful onto ungreased cookie sheet and bake at 350 degrees for 8-10 minutes.

Filling: Beat 1 egg white until fluffy. Add vanilla, flour, milk, and Crisco. Beat until fluffy. Gradually add 2 cups powdered sugar. Spread a teaspoon of filling between 2 cookies. Makes approximately 5 dozen.