Rich Custard Filling (Pastry Cream)
from Betty Crocker Cookbook, 1950 edition

Pastry cream or Crème Pâtissière is a basic staple in the bake shop. Think of it as a thick vanilla pudding or custard.  Not too sweet, this custard complements pastries such as Chocolate Eclairs and Boston Cream Pie, as well as Boston Creme Doughnuts. It can also be eaten on its own as a pudding. Try lightening it with whipped cream, or flavoring it using one of the variations below.

1/2 cup sugar
1/2 tsp. salt
6 tbsp. flour
2 cups top milk or half-n-half (milk and cream)
4 egg yolks, or 2 eggs, beaten
2 tsp. vanilla or other flavoring

Mix together the sugar, salt, and flour in a saucepan. Stir in the milk or cream. Cook over low heat, stirring [whisking helps to keep lumps from forming] until it boils. Boil 1 minute. Remove from heat; stir a little of this mixture into the beaten eggs. Blend the rest of the eggs into the hot mixture and bring to the boiling point [whisking all the time. The mixture will thicken.]. Cool and blend in the vanilla or other flavoring.

Makes about 2 cups

Variations:

Semi-sweet Chocolate: Melt 3 - 4 oz. semi-sweet chocolate; cool. Gently blend in with the vanilla once the custard has cooled.

Coffee Flavored: Dissolve 4 tsp. dry instant coffee in 1 1/2 Tbsp. of boiling water. Gently blend in with the vanilla once the custard has cooled.

Flavored Liqueur: Gently blend in 2 Tbsp. liqueur, such as Grand Marnier, Amaretto, or Frangelico, with the vanilla once the custard has cooled.