Flaming the oil of an orange peel enhances the orange flavor in a cocktail, especially one made with Lillet, an orange-based aperitif. After this technique was introduced to bartenders in New York City, they ran with the idea and added it to various liquors such as bourbon, vodka, gin, rum, and so on.
Follow these steps to flame an orange peel or any other variety of citrus.
Cut off both ends of the orange.
Insert a sharp knife or spoon between the rind and meat of the orange and carefully separate them.
Cut the rind into strips.
Make sure the citrus flesh is removed from the rind.
Place a lit match between the cocktail and the twist, which should be rind-side down; bring the rind closer to the flame, approaching at a 45 degree angle from above.
When the peel is very close to the match, give the peel a good squeeze with your thumb and forefinger to squirt the oil into the flame.
A small burst of fire should brush the liquid in your glass. After it's lit, you can choose to drop the peel into the cocktail.
Practice, practice, practice.
After a while, it will come easy.