Sean Muldoon & Jack McGarry, The Dead Rabbit, NYC

“Without the oleo-saccharum, the punch would be flat,” Jack McGarry, one of the owners of the Dead Rabbit in NYC, insists. “It’s vital.”

There’s lots of flavor locked inside the citrus peel, which is why the pros marry the peels with sugar until the fragrant essential oils emerge in a syrupy puddle.