- Combine the sugar, flour, cornstarch and a pinch of salt in a small saucepan. In a separate bowl, mix together the eggs and cream. Over medium heat, whisk the egg mixture into the sugar mixture; whisk occasionally at first to get rid of lumps, then pretty much constantly until the mixture starts to boil and thickens, about 10 minutes.
- Adjust the heat so the mixture bubbles gently. The mixture is ready when it coats the back of a spoon and a line you draw with your finger through this coating holds its shape. Stir in the butter and vanilla, and strain the mixture through a fine-mesh strainer. Let cool to room temperature before using.
— Recipe from The New York Times