Because my kids like the filling so much, I make 1 1/2 times the recipe. Amounts are in parentheses.
3 tbsp flour (4 1/2 tbsp)
1 cup milk (1 1/2 cups)
1 cup shortening (1 1/2 cups)
1 cup granulated sugar (1 1/2 cups)
1 tsp vanilla (1 1/2 tsp)
Add flour to a saucepan and gradually whisk in the milk. Cook over low-medium heat until thick. This will only take a few minutes. Cool.
When the milk mixture has cooled, in another bowl, cream the shortening, sugar and vanilla. Add the milk mixture and with an electric mixer, cream until thoroughly combined. It should be thick, and smooth. Cream for about 5 minutes. (You will see a difference, the longer you beat the mixture.)
Place one cake round on a platter. Spread with the one-third of the filling. Top with the another cake round and spread with another one-third of the filling. Top with another cake round and spread with the last of the filling. Top with the last cake round and if desired, frost just the top of the cake. (I actually make just half a recipe of the frosting when making a layer cake. When I bake this in a 9×13″ cake pan, I will make a full recipe.)
Silky Chocolate Glaze
3 (1-oz) squares unsweetened chocolate, melted
4 tbsp light corn syrup
2 cups pwd sugar
4 tbsp milk
1 tsp vanilla
Mix the above until smooth.
Store cake in the refrigerator.
Note: Sometimes I bake this in a 9 x 13″ pan. After it has cooled thoroughly, I split the cake in half, lengthwise. I return one cake half back into the pan. I spread with the filling, and top with the other cake half. Sometimes I use the glaze, but most times I don’t.