Beat sugar and butter together in a large bowl with an electric mixer until smooth. Add egg yolks, one at a time, beating well after each addition.

Beat egg whites in a separate large glass or metal mixing bowl until foamy; continue to beat until soft peaks form. (Lift your beater or whisk straight up: the egg whites will form soft mounds rather than a sharp peak.) Stir egg whites into egg yolk mixture. Stir in salt, mace, allspice, cloves, nutmeg, and cardamom.

To use the mixture, combine 1 cup hot milk and 1 ounce rum in a mug. Stir in 1 tablespoon Tom and Jerry mix.