4 ounces room temperature unsalted butter.
1/2 cup packed dark brown sugar
1 teaspoon grated orange zest
3/4 teaspoon ground cinnamon
3/4 teaspoon ground ginger
1/2 teaspoon ground nutmeg
Beat butter and spices on medium speed until combined. Spiced butter can be refrigerated for up to 2 weeks.
Combine 2 tablespoons of spiced butter with 3 tablespoons dark rum in 4 heatproof glasses. Top with 3/4 cup boiling water and stir. Top with squeeze of fresh orange juice.