Tom and Jerry Batter
Beat egg yolks until pale, then gradually add powdered sugar, rum, allspice, nutmeg, cloves, cinnamon and vanilla.
In a separate bowl, beat egg whites to stiff peaks.
Gently fold egg whites into egg yolk mixture, trying not to knock the air out of the egg whites. You will have a thick, foamy batter when it is all incorporated.
Make the drink
Pour boiling water into mugs to warm them. Let them sit for a minute or two, then dump out the water.
Add 2 - 4 tbsp. of the Tom and Jerry batter to a warm mug, then add 1 ounce of rum and 1 ounce of cognac. (*See note)
Slowly pour warm milk (or water) into the mug, stirring constantly to froth the drink. (*See note)
Top with freshly grated nutmeg. Enjoy!