Chef John Turenne at Yale notes that this bananas foster recipe, a hit in every class, was created at New Orleans's Brennan's Restaurant in the 1950s. For best results, be sure to use firm, ripe bananas.
Cut bananas in half crosswise, then lengthwise. Melt butter in a large skillet over medium heat. Add brown sugar, and cook, stirring constantly, 2 minutes. Add bananas to skillet, and sprinkle with cinnamon.
Remove skillet from heat. Stir in liqueur and rum, and carefully ignite the fumes just above mixture with a long match. Let flames die down. Return to heat, and cook 3 to 4 minutes or until soft. Serve over ice cream.