Hot Buttered Rum Cocktail

1 stick unsalted butter, softened
2 cups light brown sugar
1 teaspoon ground cinnamon
1/2 teaspoon grated nutmeg
Pinch ground cloves
Pinch salt

Bottle dark rum
Boiling water

In a bowl, cream together the butter, sugar, cinnamon, nutmeg, cloves, and salt. Refrigerate until almost firm. Spoon about 2 tablespoons of the butter mixture into 12 small mugs. Pour about 3 ounces of rum into each mug (filling about halfway). Top with boiling water (to fill the remaining half), stir well, and serve immediately.

Buttered rum mixture will keep for a month in the refrigerator.