Grilled Balsamic and Rosemary Chicken Thighs

Coat the chicken with the garlic, rosemary, salt, pepper, and extra virgin olive oil. Let sit for 5-10 minutes, or longer if you desire a marinade. Heat the balsamic vinegar in a saucepan over medium high heat. Simmer for 20 minutes until reduced by half to two-thirds. This should look like a very heavy glaze, almost honey-like in consistency. Grill 5 minutes per side on the outdoor grill until cooked through.