For the cilantro-infused rum, place cilantro and limes in an airtight container. Add the rum. Leave mixture in container for one week. This makes enough rum infusion for about 12 cocktails.

When ready to serve, fill shaker with ice and add 1 1/2 ounces of cilantro-infused rum, 1 ounce simple syrup and the lemon and lime juice. Shake well and strain into an ice-filled glass.