Pizza di visciole alla romana

• 4 egg yolks
• 1 envelope vanillina, or 4 or 5 drops vanilla extra

Put 3 egg yolks in a bowl and beat with the vanillina (if using vanilla extract, reserve to add later) and cornstarch to make a smooth cream. Grate 1 teaspoon rind (colored part only) from the lemon half.

Combine the milk, sugar, and grated rind in a large saucepan and bring to a boil.