The recipe for a Dark and Stormy is very simple, yet also very specific. Gosling’s Black Seal rum is non-negotiable. Authentic ginger beer is likewise essential. Eric Felten insists on Barritt's. The Reed's brand is available locally, so that's what I use. If you want to go DIY with fresh, small-batch ingredients, Jeffrey Morgenthaler offers a recipe for homemade ginger beer.
Measure out 1.5 oz of the Gosling's and 4-6 oz of your ginger beer of choice, and pour over ice. A lime garnish is permitted, but not encouraged. Keep it simple, and enjoy the subtle nuances of this sophisticated drink.