Beat butter, sugar, orange zest, cinnamon, ginger, and nutmeg with a mixer on medium speed until combined, about 1 minute.

Combine 2 tablespoons spiced butter with 1 1/2 ounces (3 tablespoons) dark rum in each of 4 heatproof glasses. Pour 3/4 cup boiling water over each, and stir. Top each with a squeeze of fresh orange juice.

Yield: Serves 4