In a skillet, over medium heat, sauté the onions, peppers, and mushrooms until the onions are translucent and the peppers and mushrooms are tender. Usually, 6-7 minutes and then place in a bowl and set aside.
In the same skillet, place the spinach on low heat and just allow the spinach to wilt. 1-2 minutes and set aside
In a large bowl, crack the eggs and whisk in half and half as well as salt and pepper. Whisk until well combined and the mixture is starting to become paler in color. Thiswill result in fluffier eggs.
Spray a 9x13 casserole dish with cooking spray. Place the veggie mixture and the spinach in the dish and spread it out evenly. Pour the egg mixture over the veggies. Layer in 3/4 of the cheese into the dish, and set the remaining cheese aside until later.
Layer the tater tots evenly across the whole dish. Place in the oven and bake for 55-65 minutes at 350 degrees. The eggs should be almost set and just give a slight jiggle.
Pull the dish out and cover the top with the remaining cheese. Place back in the oven for about 8-10 minutes or until the cheese is melted. Take out and garnish with parsley. Enjoy!