In a small pot:
1/2 c milk
2 1/2 Tbsp flour
Mix until smooth.
Cook slowly, stirring constantly until thick.
Set aside to cool.
In a bowl, cream together:
4 Tbsp butter
4 Tbsp crisco
1/2 c sugar
Add:
cooled milk mixture
Beat at medium speed until it has the texture of whipped cream.
Add:
1 tsp vanilla