I found this in my old recipe box. Don’t remember where it came from.
1 dark chocolate cake mix
5 T. Flour
1/2 tsp. salt
1/2 C. Shortening
1/2 C. butter or margarine
1 tsp. Vanilla
Mix cake mix as per directions on box. Bake in jelly roll pan that is greased and lined with wax paper. Bake 30 minutes. Cool cake and remove from pan and wax paper. Cut into 4ths and split each fourth horizontally.
Mix milk, flour and salt slowly so as not to have lumps and cook over medium heat until very thick. Cool in refrigerator.
Add the rest of ingredients one at a time beating after each addition. Beat until fluffy. Fill slices and add tops. Store in refridgerator.