In a large mixing bowl, whisk together ½ cup extra-virgin olive oil, ¼ cup balsamic vinegar, 2 tablespoons low-sodium soy sauce, and 1 tablespoon Worcestershire sauce. Add the juice of one lemon, ⅓ cup packed brown sugar, 1 tablespoon dried rosemary, 1 tablespoon Dijon mustard, salt, black pepper, and 1 teaspoon garlic powder. Mix until fully combined, and the sugar dissolves.

Take ½ cup of the marinade and set it aside in a small bowl for later basting.

Place your chicken pieces into a resealable plastic bag. Pour the remaining marinade over the chicken, ensuring every piece is coated well. Seal the bag tightly, then gently massage it.

Refrigerate the marinated chicken for a minimum of 2 hours, ideally letting it sit for 4-6 hours, or up to 24 hours.

About 15 minutes before cooking, preheat your grill to medium-high heat.

Remove the chicken from the marinade, pat it dry with paper towels.

Place the seasoned chicken pieces directly on the grill. Grill for about 5-6 minutes on one side, then flip and continue cooking for another 5-6 minutes.

During the grilling process, baste the chicken occasionally with the reserved marinade.

After grilling, allow the chicken to rest for about 5 minutes before slicing.