Preheat the oven to 375°F (190°C).

Grease a 9x13-inch baking dish with olive oil or butter.

In a skillet, heat olive oil over medium heat. Sauté chopped onion and minced garlic for 3-4 minutes.

In a large bowl, combine zucchini, corn, cherry tomatoes, sautéed onion, and garlic. Season with oregano, salt, and pepper.

Spread the vegetable mixture evenly into the greased baking dish.

Sprinkle mozzarella cheese over the vegetable layer.

Mix Parmesan cheese with panko breadcrumbs and sprinkle over the mozzarella layer.

Drizzle olive oil over the breadcrumb topping.

Bake for 30-35 minutes until golden brown.

Let it cool for 5-10 minutes, then garnish with fresh basil or parsley before serving.