Heat the oil in a pan over medium-high heat. Add the sliced zucchini and chopped peppers, season with salt and pepper.
Cook for 6-7 minutes or until tender. Transfer into a bowl and allow to cool as you prepare the egg mixture.
Preheat oven to 350°F (180°C). Grease a 9-inch pie or square tin and set aside.
In a large bowl, whisk the eggs, egg whites, milk, garlic powder, salt, and pepper until combined. Arrange the veggies into the
prepared pan and top with the chicken slices. Then pour the egg mixture on top, and sprinkle with grated parmesan cheese.
Bake for 45 minutes or until filling is set and no longer jiggles. Store tightly covered in the refrigerator for up to 4 days.