Step 1: Pound the chicken breasts. Place each chicken breast individually into a large zip-top bag or between two sheets of plastic wrap. Using a meat mallet or a heavy rolling pin, pound them to an even thickness of about ½ to ¾ inch. This ensures even cooking.
Step 2: Prepare the flavorful marinade. In a medium bowl or a large measuring cup, whisk together the olive oil, garlic powder, Italian seasoning, minced fresh garlic, fresh lemon juice, optional sugar, salt, and black pepper until well combined.
Step 3: Marinate the chicken. Place the pounded chicken breasts into a large zip-top bag or a shallow dish. Pour the prepared marinade over the chicken, ensuring each piece is fully coated. Seal the bag (or cover the dish) and refrigerate for at least 30 minutes, or for best results, 4 to 12 hours.
Step 4: Preheat your grill. Heat your outdoor grill to a high temperature (around 450-500°F or 230-260°C). Lightly oil the grill grates to prevent the chicken from sticking.
Step 5: Grill the chicken to perfection. Place the marinated chicken breasts on the hot, oiled grill grates. Grill for 2-4 minutes per side, with the lid closed, until beautiful grill marks appear and the internal temperature reaches 165°F (74°C). Use a meat thermometer to check the thickest part.
Step 6: Rest and serve. Once cooked, remove the chicken from the grill and let it rest on a cutting board for at least 5 minutes before slicing or serving. This allows the juices to redistribute, ensuring maximum juiciness.