Crème pâtissière

In a 3-quart mixing bowl, beat the sugar into the egg yolks with a wire whisk until the mixture is pale yellow and forms the ribbon.

Beat in the flour.

While beating, pour the boiling milk onto the egg yolk mixture in a thin stream.

Pour the mixture into a saucepan and set over moderate heat, stirring constantly.

Bring to the boil slowly while stirring well to avoid lumps.

When it reaches the boil, stir for 2 to 3 minutes to cook the flour well, being careful not to burn it in the bottom of the pan.

Remove from the heat and beat in the butter followed by the vanilla extract.

Cover the surface with a sheet of parchment paper to prevent a skin from forming and allow to cool