Mix as directed on box. Spread into 2 greased and floured 9 x 13 inch pans. Bake 20-30 minutes at 350 degrees.
Combine and cook until thick paste: 1 1/2 cups milk and 5 tablespoons flour; cool.
Beat until creamy: 1 cup sugar, 1 cup Crisco, 1/2 cup butter, and 1 teaspoon vanilla. Add cooled paste. Beat 7 minutes. Spread on cooled cakes. Refrigerate 1 hour.
Boil 1 cup sugar, 1/2 cup butter, and 1/2 cup milk for 2 minutes. Remove from heat and add 1 cup chocolate chips. Stir until chips melt. Pour over filling. Refrigerate. This recipe makes 2 (9 x 13 inch) pans and freezes well.