1 yellow cake mix
1 pkg. vanilla instant pudding
1 c. water
1/3 c. oil
3 eggs
1/2 tsp. salt
(or use a pudding plus cake mix with 1/2 teaspoon salt)

FILLING:

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

Combine flour and water, cook until thick, and cool in refrigerator. Combine sugar, butter, shortening and vanilla. Beat until thick. Add to cooled flour and water mixture. Mix cake mix, pudding, water, eggs, oil and salt. Pour into a waxed paper lined 9 x 13 inch pan. Bake at 350 degrees for 35 to 40 minutes until done. Cool, remove cake from pan, slice lengthwise with thread, spread filling between layers, and sprinkle with powdered sugar.