2 tablespoons flour
1 cup light cream or milk
1/8 teaspoon salt
3/8 cup sugar
4 egg yolks
1 teaspoon vanilla extract
Combine flour with 1/4 cup cream. Stir until smooth. Gradually add the remaining 3/4 cup cream. Place in a heavy saucepan. Stir in salt and sugar. Cook over medium heat, stirring until mixture becomes as thick as a medium white sauce.
Stir a little of the hot sauce into egg yolks. Then pour egg yolks into saucepan, stirring briskly. Return pan to low heat for a few minutes to thicken a little more, continuing to stir. Be careful not to let the sauce boil. Remove from heat. Add vanilla. Cool as quickly as possible.
In order to prevent a skin from forming on top of thick pastry while it is cooling, melted butter may be brushed over it. Stir pastry cream before using.