Cut bananas into slices, and have all ingredients prepped and alongside the grill ready to use.
Heat skillet over medium heat. Add butter, cinnamon, and brown sugar to the pan.
Stir until sugar dissolves.
Stir in banana liqueur.
Add bananas to the pan. Cook until softened and start to brown lightly. Add pecans if desired
Pull pan off heat, slowly add the rum
Cook for about 10 seconds until rum is warmed then ignite with a long match or grill lighter (at the edge of the pan). If for some reason it does not ignite, carefully return the pan to the grill and cook for a minute or two until the alcohol burns off.
Bananas are finished once the flames go out. Spoon over French toast.
If desired, top with whipped cream or vanilla ice cream. Serve immediately.