2 egg yolks
2 tablespoons cornflour
2 cups milk
2 tablespoons sugar
2 teaspoons vanilla extract
Whisk egg yolks and cornflour to a smooth paste with a little of the milk.
Heat remaining milk until it boils.
Slowly pour the yolk/cornflour mix into the hot milk while whisking. Continue to whisk until thick and smooth. Whisk in vanilla and serve.
Note: Milk must boil or custard will not thicken.
Source: Best Recipes