The custard is prepared by heating milk with a vanilla pod, then mixing egg yolks with sugar and adding the mixture to hot milk. The sauce is cooked over low heat until it thickens, stirring constantly to prevent it from hanging. English cream is a source of protein and vitamins, in particular vitamin A and vitamin D, which are important for the health of the skin and bones. It is also a source of calcium, phosphorus and magnesium, which are important for the normal operation of the organism.