Melt butter over low heat. Once melted add brown sugar, cinnamon and vanilla extract.
Stir mixture on low heat until sugar dissolves.
Remove from heat and add banana liqueur and spiced rum.
Set 1/4 cup of the slurry aside for the fondue and store the rest in a glass container. (This is extra, slurry will last in fridge for 7 days or freezer for 3 months)
In fondue pot liner melt 8 oz white chocolate, stirring as needed.
Once melted add slurry (1/4 cup) and 1 banana sliced and stir.
(Optional): Flambé with 151 proof Rum, allow sugar to begin to caramelize. (This will create small crunchy pieces that are heavenly!)
Turn burner to low (or put out flame on fondue pot), stir and enjoy!