To make grilled grapefruit juice: slice one grapefruit into 1/2 inch thick pieces. Oil grates of grill so that grapefruit doesn't stick. Char grapefruit slices and let cool. Reserve one slice for garnish, and juice remaining slices.
Combine all ingredients into a cocktail shaker and shake with ice.
Elliott Clark, also known as the Apartment Bartender, is a well-respected tastemaker, cocktail creator, spirits writer, and photographer in the spirits industry. What started out as a hobby for making cocktails at home has developed into a full-blown career that takes Elliott all over the world mixing drinks for some of the world’s most notable brands, and making the world of spirits more accessible to the at-home cocktail enthusiast.