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

In a large skillet, heat olive oil over medium heat. Add chopped onion and minced garlic, sauté for 3-4 minutes until translucent.

In a mixing bowl, combine sliced zucchini, corn, halved cherry tomatoes, sautéed onion and garlic, dried oregano, salt, and black pepper. Toss gently.

Transfer the vegetable medley into the greased baking dish, spreading it evenly.

Sprinkle shredded mozzarella cheese over the vegetable mixture.

In a small bowl, mix Parmesan cheese and panko breadcrumbs, then sprinkle over the mozzarella layer.

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

Allow to cool for 5-10 minutes, then garnish with freshly chopped basil or parsley before serving.