Begin by washing and finely chopping your zucchini, bell peppers, and onion into uniform pieces to ensure even cooking.

Set your Instant Pot to sauté mode and add a drizzle of olive oil. Once heated, add onions and minced garlic; cook until translucent.

Add zucchini, bell peppers, and spinach, stirring gently. Cook until spinach wilts and veggies are just tender.

In a mixing bowl, combine the sautéed vegetables with eggs and Parmesan cheese, stirring until well incorporated.

Pour the vegetable and egg mixture into the Instant Pot, spreading it evenly across the bottom.

Secure the lid on the Instant Pot and cook on high pressure for 10 minutes.

Let the pressure release naturally for about 10 minutes, then carefully switch the valve to venting.

Open the lid and witness the golden perfection of your casserole, ready for a delightful meal.