In a small bowl, beat the butter, brown sugar, cinnamon, cloves, ginger, and nutmeg until smooth. Chill for 20-30 minutes or until firm.
While waiting, brew the coffee.
Spoon 1 tablespoon of the spiced butter into a coffee mug. Pour 1 ounce rum over the butter and top with 1 cup of coffee. Stir to combine.
Repeat with the remaining butter, rum and coffee.
Serve immediately with whipped cream and a sprinkle of nutmeg.