Preparation

1. Let the eggs come to room temperature.
2. Sift together the flour and corn starch.

Directions

1. Warm the milk.
   Heat the milk in a large saucepan over medium heat. Stop just before it boils.
2. Mix the yolks and sugar.
   Whip the egg yolks and sugar together in a bowl until the mixture turns whitish and begins to thicken.
3. Add flour.
   Add the sifted flour mixture to the egg mixture and beat until completely mixed.
4. Add milk.
   Pour about a third of the warmed milk into the bowl, a little at a time, while beating with a whisk. When the first third is well mixed, pour the remainder in all at once and stir until mixed.
5. Strain the batter.
   Pour the batter back into the milk pan through a mesh strainer; this will result in a smoother custard.
6. Heat and stir.
   Heat the pan on medium-high, stirring constantly from the bottom up with a whisk. When it begins to thicken, reduce heat to medium and continue to stir. It will first become stiffer, then should become lighter and easier to stir; remove from heat at that point.
7. Add butter and vanilla.
   Add the butter and vanilla extract, then stir until completely blended.
8. Cool in a shallow pan.
   Pour the cream into a thin layer in a cake pan or other flat pan. Lay a sheet of plastic wrap on top of the cream and push it down so it is in contact with the surface of the cream; this will keep it from drying out. Let it cool slightly before putting it in the refrigerator to chill.
9. Stir custard cream and use.
   When you are ready to use the custard cream in a recipe, transfer it back into a bowl; it should be solid enough that the wrap comes off clean and it peels away from the pan cleanly. Stir until the creamy texture returns. If you prefer softer, creamier texture you can mix in heavy cream at this point, a little at a time, until the mixture reaches the thickness you like.