Add all ingredients to a cocktail shaker and fill it 3/4 with ice.
Shake until chilled, then strain into a cocktail glass.
Garnish with a banana slice.
Notes
Don't have time to make the banana syrup?
Try substituting with a high quality banana liqueur like Giffard's Banane du Brasil and a touch of simple syrup. Here's a good starting point:Ingredients:
2 oz white rum
1 oz lime juice
1/2 oz - 3/4 oz Giffard Banane du Bresil
1/2 oz simple syrup
Instructions:Combine all ingredients in a cocktail shaker and fill it 3/4 with ice. Shake until chilled, then strain into a cocktail glass and garnish with a banana slice.