Chocolate Twinkie Cake

1 (9 x 13) inch chocolate cake mix

5 tablespoons flour

1 cup milk

1 cup sugar

1/2 teaspoon salt

1/2 cup vegetable shortening

1 teaspoon vanilla

 

Bake cake according to package directions and cool. 

 

Mix flour and milk. Cook over low heat until thick, remove from heat and cool. Place shortening, butter, salt and vanilla in mixing bowl and mix. Add cooled flour and milk mixture and beat at high speed until filling is like whipped cream. Cut cooled cake in half lengthwise and put on filling. Place top back on and frost with favorite icing.