Prepare the chicken: Place your hand on top of each chicken breast and carefully slice each breast in half, lengthwise. Make sure to trim any excess fat from the chicken. Place the chicken in a mixing bowl or a ziplock bag for easy cleanup.
Prepare the marinade: In a medium bowl, combine the lemon, olive oil, Italian seasoning, garlic powder, salt, pepper, and honey, and mix well to combine.
Marinate the chicken: Pour the marinade on the chicken, cover, and marinate for at least 30 minutes.
Cook the chicken: Heat a grill, grill pan, or cast iron pan to medium heat. Place the chicken on the grill and cook each piece for 3 minutes per side until the internal temperature reaches 165 degrees Fahrenheit. You can use a meat thermometer to ensure you have reached the right temperature. This will help you ensure that the chicken is fully cooked and safe to eat. Take the chicken off the grill, put it on a plate, and keep it aside. Let it rest until it is time to assemble the sandwich.
Prepare the sauce: To make the sauce, add all ingredients to a small bowl and mix well to combine into a thick, silky sauce.
Assemble the sandwich. To assemble the sandwich, spread some sauce on each half of the bread. I use Ciabatta Square, which I like for this type of recipe. I also used it for this EASY BRUSCHETTA RECIPE. Layer the baby spinach on the bottom of the bread, then add chicken and avocado slices, and top it off with sliced tomatoes and red onions. Add more sauce on top. Finish by placing the top bun. And Enjoy! This recipe makes four sandwiches.