1. Preheat oven to 350°. Spray a 9” x 13” pan with baking spray.
2. Mix the following in a large bowl: minced garlic, Italian seasoning, butter, olive oil, 1/4 cup Parmesan cheese and 1/4 cup Romano cheese, as well as salt and pepper.
3. Add the zucchini slices, tomato slices and onion slices to bowl. Mix together.
4. Add the mixture of all ingredients into the sprayed 9”x13” pan (when adding ingredients, reserve a few zucchini slices and tomato slices to layer the top of dish).
5. Once the zucchini and tomato slices cover the top of the dish, sprinkle the top with a 1/4 cup of Parmesan cheese, 1/4 cup of Romano cheese and a 1/4 cup of mozzarella cheese.
6. Bake for 30 minutes, covered with foil.
7. Remove foil and bake for an additional 5-10 minutes or until cheese is bubbly and slightly browned.