1 yellow cake mix or chocolate
1/3 c. oil
1 sm. pkg. vanilla or chocolate instant pudding
3 eggs
1 c. water
1/2 tsp. salt

FILLING:

5 tbsp. flour
1 c. water
1 c. sugar
1/2 c. butter
1/2 c. shortening
2 tsp. vanilla

Mix together first group of ingredients and pour into a waxed paper-lined 9 x 13 inch pan. Bake at 350 degrees for 35 to 40 minutes. Cool completely and remove from pan. Slice cake lengthwise using heavy thread. Replace bottom half of cake in pan.

FILLING: Combine flour and water for filling and cook until thick. Completely cool. Beat sugar, butter, shortening and vanilla until light and fluffy. Combine flour mixture with cream mixture and beat until fluffy. Spread filling on bottom half of cake. Replace top of cake and sprinkle with powdered sugar. Be sure to stir flour and water while its cooking, so it doesn't become lumpy.