In a medium bowl combine sugar, butter, vanilla, cinnamon, cloves, and 1 teaspoon nutmeg; beat well. Refrigerate until ready to use.
Place 1 heaping teaspoon sugar mixture into six 8 oz Irish Coffee mugs or any heatproof mugs; add 2 ounces rum. Finish filling each mug with boiling water; mix well. Sprinkle with nutmeg.