Necessity is certainly the mother of invention in the restaurant business, mainly because you’ve always got to figure out something to do with the leftovers. At Chez Henri (1 Shepard St., Cambridge, Massachusetts; 617-354-8980), a small restaurant serving a mix of French and Cuban cuisine, chef-owner Paul O’Connell found himself with an oversupply of lemon-flavored rum. O’Connell turned to bartender K.C. Cargill to do something with the spirits, and from this challenge was born one of Chez Henri’s most popular cocktails.

1 C sugar
1/2 C water
1 oz. Bacardi Limoné Rum
1/2 C fresh grapefruit juice
Splash cranberry juice
In a saucepan, make a simple sugar syrup by blending sugar and water. Bring to a boil and stir until no sugar crystals remain. Remove from heat and cool. In a cocktail shaker with ice cubes, pour rum, grapefruit juice, cranberry juice, and 1/2 ounce syrup. Shake until cold, then strain into a martini glass. After a few moments the two juices should separate into colored layers.