Get ready to bake! Preheat your oven to 400°F (200°C) and line a baking tray with parchment paper for effortless cleanup.
Grab a sharp knife and carefully make 5-6 deep slices across the top of each chicken breast, going about three-quarters of the way through – make sure not to cut all the way! These will be the little pockets for your delicious fillings.
Drizzle the chicken with olive oil, then generously rub it all over with the garlic herb seasoning, salt, and pepper. Don't forget to get into those cuts for maximum flavor!
In a small bowl, whisk together the softened cream cheese, bright lemon zest, and 2 tablespoons of the Parmesan cheese until the mixture is wonderfully smooth and creamy.
Now for the fun part! Gently spread a little bit of the cream cheese mixture into each slice you made on the chicken. Then, carefully tuck in the zucchini and tomato slices into the same cuts. It will look beautiful and vibrant!
Place your stuffed chicken breasts onto your prepared baking pan. Pop them in the oven and bake for 10 minutes.
After 10 minutes, pull them out and sprinkle the remaining Parmesan cheese generously over the chicken. Return the pan to the oven and bake for another 10-15 minutes, or until the chicken is thoroughly cooked (reaching an internal temperature of 165°F or 74°C) and the veggies are perfectly tender.
Serve hot and savor your healthy, flavorful Hasselback Chicken!