Pour chestnut liqueur and bourbon into a heatproof glass or mug.
Add hot coffee and stir to combine.
Float cream on top by pouring over the back of a spoon.
Top with whipped cream and a sprinkle of nutmeg or cinnamon, if desired.
Notes
Use milk instead of cream for a lighter drink. Swap bourbon for brandy for a sweeter flavor. For a cold version, use cold brew and shake with ice, then strain.