- 10 fluid ounces milk, or to taste
- 2 teaspoons brown sugar
- 1 teaspoon vanilla extract
- 1 1/2 fluid ounces rum
- 1 teaspoon butter
- 1 pinch ground nutmeg
- Fill a microwave-safe mug with milk; stir in brown sugar and vanilla extract.
- Heat milk mixture in microwave until almost boiling, about 1 minute. Stir rum into milk mixture and float butter on top; sprinkle with nutmeg.