2 ounces dark rum (Goslings is the classic choice for this one, but I'm pouring Trigo Reserva Añeja, which I picked up on my last visit to Puerto Rico)
4 ounces ginger beer (such as Reed's Original Ginger Brew)
Lime wedge for garnish
Fill Collins glass with ice. Add rum and ginger beer and stir to mix. Garnish with lime wedge.