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