Add milk and 3/4 of the cream to a saucepan and heat it till the liquid starts to steam.
Mix the egg batter with milk and cream.
Re-heat the milk-egg mixture on medium heat now, and keep stirring it until the mixture is thick enough to stick to the spoon.
Add nutmeg and vanilla extract to the mix and allow it to cool. You can keep it in the refrigerator for 3-4 days for optimum temperature and consistency levels.
Notes
The FDA recommends heating - or pasteurizing - the mixture to 160 degrees to avoid any risk of salmonella.