Heat the olive oil in a large skillet over medium heat. Add in the onions and sauté for 2-3 minutes. Transfer the onions to a large bowl and set aside. Add the zucchini and sauté for 5-7 minutes until softened. Transfer zucchini to the same bowl.
Add parmesan, breadcrumbs, salt, garlic powder, onion powder, Italian herb blend, mozzarella, ham, eggs, and pepper to the bowl. Mix until well combined.
Transfer mixture to a 7x11 inch baking dish. Spread evenly. Sprinkle additional breadcrumbs, parmesan, and Italian herbs on top. Bake for 25-30 minutes. Turn on broiler at the end for 1-2 minutes to brown the top.
Notes
This zucchini bake is versatile and can be served hot or cold. Great for a family dinner or a side dish.