This classic French custard can be flavored with vanilla, rum, or kirsch. It can be made up to two days ahead or one hour before needed.
1/2 cup sugar 6 egg yolks 1/4 cup flour pinch salt 2 cups milk 1 tsp. vanillaMix half the sugar, egg yolks, flour, salt, and 1/2 cup of the milk in a small bowl and mix well to blend.
In a medium saucepan, heat the rest of the milk and sugar together. As it comes to a boil, whisk in the egg yolk mixture. Let the mixture resume boiling, blending well with a whisk to make sure bottom does not burn. As mixture thickens, remove from heat. Let stand 2-3 minutes, then stir in vanilla. Cool, then cover tightly with plastic wrap (the wrap should lie right on the surface of the custard: this prevents a "skin" from forming) and store in refrigerator until needed. Blend well with wooden spoon before using. Depending on size of puffs or how much filing is used, recipe may have to be repeated.