Place the butter, sugar, cinnamon, and salt in a large frying pan.

Heat over medium-high heat.

Cook, stirring constantly, until a bubbly and slightly thickened caramel forms, about 3 minutes.

Add the bananas, cut side down, in a single layer, keeping them from touching.

Cook until the bottoms are coated with caramel, about 1 minute.

Flip the bananas over carefully with two forks or a spatula.

Remove the pan from the heat.

Add the rum and let it sit a few seconds to warm up.

If using a gas stove, place the pan back on the burner over medium heat and slightly tip it to ignite the alcohol.

If using an electric stove, light a match or grill lighter and lower the flame toward the rum in the pan until it ignites.

Remove the pan from the stove and let the flames burn off, about 1 to 2 minutes.

Arrange the bananas on a serving dish.

Pour the sauce over them.

Top with vanilla ice cream if desired.