In a large saucepan or skillet, heat butter, sugar, and cinnamon over medium-high heat. Cook, stirring often until butter is melted and mixture is bubbly, about 4 minutes.
Add bananas. Cook, gently stirring often, until tender, about 4 minutes.
Add the rum and remove from heat. Using a long lighter or long match, carefully ignite rum, swirling pan constantly, until flames die out, about 30 seconds. (If you feel unsafe doing this step, simply add the rum and continue cooking for about 1 minute before removing it from the heat.)
Serve immediately over ice cream.
When igniting the rum, make sure you don’t have any other burners on. Keep your sleeves rolled up, hair ties back, and keep a large metal lid handy in case you have to smother the flame.
Don’t have ice cream? Try adding a dollop of whipped cream instead.
Add a splash or two of heavy cream before adding the bananas for an even richer and creamier Bananas Foster sauce.
Slice the bananas right before you start cooking. Once sliced, the bananas begin to oxidate and won’t keep well for long.
A light-colored or stainless steel pan is ideal as it is more challenging to keep an eye on the dark caramel sauce in a dark pan.