How to Make It
Stir together butter, brown sugar, apple pie spice, and vanilla in a small bowl until combined. Store, covered, in refrigerator until ready to prepare drink.
For each drink: Spoon 1 tablespoon of the butter mixture in bottom of a coffee mug; pour 1/3 cup hot water over butter mixture, and stir until melted. Top with 1/4 cup RumChata, stirring well. Garnish with a cinnamon stick; serve immediately.