1/2 c. balsamic vinegar
1 tbsp. olive oil
1 tbsp. fresh rosemary, chopped
1 clove garlic, minced
1/2 tsp. salt
1/4 tsp. pepper
4 boneless, skinned chicken breasts (4 oz. each)

Combine everything except chicken in bowl or measuring cup. Pour over chicken. Marinate covered in refrigerator for 30 minutes. Broil or grill chicken until done.