Here's the recipe:

1. Fill a cocktail shaker halfway with ice. Add 2 oz Gosling’s Black Seal rum and ¼ oz freshly squeezed lime juice. Shake vigorously until the shaker is frosty.

2. Fill a rocks glass with ice and strain the mixture into the glass.

3. Top the cocktail off with 2 oz ginger beer and stir to blend.

4. Garnish with a piece of crystallized ginger and a lime wheel, and enjoy!

Recipe source: Food & Wine