Fill coffee mug 3/4 full with hot water. Stir in batter until dissolved. Add rum and serve with a stir stick.
Batter Mix: 1 lbs. brown sugar, 1/2 lbs. salted butter (softened), 2 teaspoons ground cinnamon, 2 teaspoons ground nutmeg, 1/2 teaspoon ground allspice, pinch of ground clove, 1 teaspoon vanilla extract. In a mixing bowl blend all ingredients together with a hand mixer. Store at room temperature. For a buttered pumpkin batter, simply add pumpkin pie puree to taste (about 1 small can) to batter mix and blend thoroughly.