Separate egg yolks from egg whites and put in two separate bowls.
Add cream of tartar to the bowl of egg whites and beat until stiff peaks have formed.
In the other bowl, beat egg yolks, sugar and stick of butter until thickened, then add the remaining ingredients of vanilla extract, cinnamon, cloves, nutmeg and rum.
Gently fold the stiff egg whites into the mixture.
Cover and store your batter in the refrigerator until it is time to make the drinks. Preferably within a few hours.
Making The Drinks
Gently heat milk in a saucepan.
Warm your mug by rinsing it with very hot water.
To each cup add 1 heaping tablespoon of Tom And Jerry batter, 1 oz of rum and 4 oz of hot milk (hot water can be substituted).
Stir until foamy.
Garnish with ground nutmeg.
Notes
The batter should be refrigerated when not in use and consumed the same day.