Whoopie pies

1/2 cup baking cocoa
1/2 cup hot water
1/2 cup shortening
1-1/2 cups sugar
2 eggs
1-1/2 tsp. vanilla
2-2/3 cups flour
1 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
1/2 cup buttermilk
Filling:
3 tbl. flour
dash salt
1 cup milk
3/4 cup shortening
1-1/2 cups powdered sugar
2 tsp. vanilla

1. Combine the cocoa and water, mixing well. Cool for 5 minutes. Then in a separate bowl, cream the shortening and sugar. Add the cocoa mix, eggs and vanilla. Mix well. Combine the dry ingredients together. Add to the creamed mixture alternating with the buttermilk. Drop by rounded table-spoons 2 inches apart onto a greased cookie sheets. Flatten slightly with the back of a spoon.
2. Bake in a 350 degree oven for 10-12 minutes or firm to the touch. Remove and cool.
Filling: In a saucepan, combine the flour and the salt. Gradually add in the milk and whisk until smooth (approx. 5 minutes). Remove from the heat, cover and cool in the refrigerator. Cream the shortening, sugar and the vanilla. Add to the chilled mixture and beat for 5 minutes or until fluffy. Spread the filling on half the cookies made, then cover the filling with the remaining cookies. Keep refrigerated.