- 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 a ribbon.
- Beat in the flour.
- While beating continuously, pour the hot 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, then 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.
Notes, tips, and variations