jeannesher and molly99, these two were posted by Tami on recipelink in response to someone looking for an old BC recipe for cream puff filling. Maybe it is what you want.
I have a very old version of Betty Crocker Cookbook and I see two that might be what you want.
Cream Filling
1/3 cup granulated sugar
3 Tablespoons all-purpose flour
1/4 teaspoon salt
1 1/4 cups milk
1 beaten egg
1 Tablespoon butter
1 teaspoon vanilla
In saucepan, combine sugar, flour and salt. Gradually add milk; mix well.
Cook and stir over medium heat till mixture thickens and boils; cook and stir 2 minutes longer. Very gradually stir the hot mixture into the egg return to saucepan. Cook and stir till the mixture just boils. Stir in butter and vanilla; cover surface with waxed paper or clear plastic wrap. Cool(Don't stir during cooling) Makes 1 1/2 cups.
FRENCH CUSTARD FILLING
1/3 cup sugar
1 tablespoon all-purpose flour
1 tablespoon cornstarch
1/4 teaspoon salt
1 1/2 cups milk
1 slightly beaten egg yolk
1 teaspoon vanilla
1/2 cup whipping cream, whipped
In saucepan, combine sugar, flour, cornstarch and salt. Gradually stir in milk. Cook and stir until mixture thickens and boils; cook and stir 2-3 minutes longer. Stir a little hot mixture into egg yolk; return to hot mixture. Cook and stir till mixture just boils. Add vanilla; cool. Beat smooth; fold in whipped cream.