Cream butter with brown sugar and several pinches of nutmeg and into each of 4 flameproof mugs add some of the butter-sugar mixture, 3 cloves, and 1 each cinnamon stick, lemon peel, orange peel, and 2 oz. of rum. Stir well and ignite and blaze of a few seconds. Pour in coffee and stir well. Top with whipped cream if you wish.