Beat the eggs, the sugar, the salt, and the vanilla together.
Scald the milk and add it very slowly, stirring constantly (see tempering).
Pour the mixture into a greased or buttered baking dish or several small greased heat-proof molds.
Place the baking dish or the molds in a pan of water in a slow oven (300–325°F / 150–160°C) and bake for between 30 and 40 minutes.
Test if the custard is cooked with a knife, which will come out clean when the custard is thoroughly baked.