Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish.

In a medium skillet, heat olive oil and sauté diced onion and minced garlic until soft and fragrant, about 3-4 minutes.

In a large mixing bowl, combine sliced zucchini, corn kernels, and halved cherry tomatoes with the sautéed onion and garlic. Season with dried oregano, salt, and black pepper, then toss gently.

Spread the vegetable mixture evenly in the greased baking dish.

Sprinkle shredded mozzarella cheese evenly over the vegetable mixture.

In a small bowl, combine freshly grated Parmesan cheese and panko breadcrumbs. Sprinkle this mixture over the mozzarella.

Drizzle olive oil over the breadcrumb topping and bake for 30-35 minutes until golden brown.

Allow to cool for 5-10 minutes before garnishing with fresh basil or parsley and serving.