Preheat your oven to 375°F (190°C) and lightly grease a 9-inch pie dish or skillet with olive oil.

In a skillet over medium heat, add a tablespoon of olive oil and sauté finely chopped onion for about 3 minutes until translucent.

Incorporate grated zucchini and minced garlic, cooking for an additional 5-6 minutes until the zucchini is tender.

In a large mixing bowl, whisk together eggs, milk, and heavy cream, then add dried basil, oregano, salt, and pepper.

Spread the cooled vegetable mixture in the greased pie dish and layer with diced tomatoes, mozzarella, and Parmesan cheese.

Pour the egg mixture evenly over the top, then bake for 35-40 minutes or until the top is golden brown.

Remove from the oven, let cool for 5-10 minutes before slicing, and serve warm or at room temperature.