Heat a large skillet over medium-high heat. Spray with nonstick spray and add sliced squash and zucchini, chopped pepper, garlic, and thyme. A little pinch of salt and pepper, too. (The rest of the salt and pepper called for in the recipe goes into the egg mixture, so just use a pinch here). Stirring frequently, cook for 6-7 minutes or until veggies are tender. Spoon into a bowl and allow to cool as you prepare the egg mixture.

Preheat oven to 350°F (177°C). Spray a 9-inch pie dish or square pan with nonstick spray. Set aside.

In a large bowl, whisk the eggs, egg whites, milk, salt, and pepper together until thoroughly combined. Arrange veggies into the prepared pan. Top with shredded cheese, then pour the egg mixture on top. Sprinkle with grated parmesan cheese.

Bake for 45 minutes or until filling is set and no longer jiggles. Cool for 10 minutes on a wire rack before slicing and serving. (Note that it can be a little watery on the bottom, even after cooking and cooling, since there are so many vegetables with no crust.)

This quiche makes great leftovers! Store tightly covered in the refrigerator for up to 4 days.