This is a fantastic dessert that can be prepared tableside if you have a portable gas burner. The one I have uses canned butane cartridges and produces about 9500 BTUs. Of course, it can also be done on your stovetop, as well.
Scoop ice cream into 2-3 individual serving dishes (depending on how large you want each serving to be) and place in freezer. The ice cream should be firm and the serving pieces should be ice cold by the time you are ready to make the dessert.
Pre-chill the bananas in the refrigerator. Do not use overly ripe bananas. The peel should be smoothly yellow with minimal spots or browning.
If you'll be using the orange zest, go ahead and do that now (it won't take much, probably 4-5 swipes on a medium orange) and set aside.
Over medium heat, melt butter in an 8-9" sauté pan. Do not brown or overheat the butter.
Once melted, add the brown sugar and stir until dissolved.
As the sugar begins to caramelize, add the créme de banane and triple sec. Stir to blend everything smoothly. Reduce heat to its lowest setting.
Peel and slice bananas into the sauce. This can be done with as much or as little flair as you desire. This is definitely a dessert whose incredible taste is enhanced by the style of its preparation, so I always like to make a bit of a show of it.
Increase heat back to medium and cook the sliced bananas for about 2 minutes, until they become softened and glossy in appearance.
In the final seconds of their cooking, retrieve the dishes of ice cream from the freezer. They should be frosty cold.
Increase the heat to medium high and have a long-reach lighter ready in your hand. Pour the 151-proof rum into the pan, wait a beat, then ignite. Watch those eyebrows! If you are a practiced cook, and are using a gas burner, you can ignite the rum vapors by tilting the sauté pan slightly into the burner flame.
Once the alcohol is burned off, which will only take a few seconds, turn off the burner and spoon the bananas and sauce over the scoops of ice cream. This should yield 3 small desserts or 2 decent-sized ones. It's a very sweet and rich dessert, so small portions are not a bad thing!
If you want to add a small pinch of orange zest, do so immediately before serving.