Bring milk, cream and vanilla to the boil taking care not to burn the bottom of the pan.
2
In a bowl, cream the egg yolks and sugar with a whisk until pale and creamy. Slowly incorporate the hot milk, whisking as you go.
3
Return to saucepan and cook over a very low heat, stirring bottom of pan continuously with a flat wooden spoon, until sauce begins to thicken and will coat the back of a spoon. Remove from heat and stir for 2 minutes while cooling.
