Add bourbon, banana liqueur, and bitters to a shaker filled with ice and stir vigorously for 30 seconds or until thoroughly chilled.
Strain into a double old-fashioned glass with a large ice cube.
Add garnish and serve.
Banana Garnish
Peel and cut banana into 1/2" thick slices.
Add butter and brown sugar into a saucepan on high heat. When butter is melted, add bananas.
Sauté bananas until they begin to cook. When they are almost done, add a splash of bourbon into the pan and light it on fire to glaze and caramelize the bananas.
Blow out the flame.
Fold an orange peel over a banana slice and hold in place with a bamboo toothpick.
Notes
One of the biggest factors is using a high quality banana liqueur. You can experiment with different bourbons, but you absolutely do not want to skimp on the banana.