Preheat oven to 375℉ and grease a 9 x 13-inch baking pan with cooking spray. Whisk together eggs and egg whites in a large bowl. Set aside.
Heat olive oil in a large nonstick pan over medium heat. Add in onions and sauté for about 5 minutes. Add in broccoli, mushrooms, and spinach; cook for another 4 minutes, or until veggies are tender. Add in garlic and sauté for another 30 seconds. Season with salt and pepper. Mix with eggs and pour into prepared baking pan.
Bake in preheated oven for 20 to 30 minutes, or until the eggs have fully cooked through. Use a glass (or some sort of circle cutter) to cut eggs into a circle the size of your English muffins.
Toast English muffins to your liking. Place cheese on one side and turkey on another. Broil in the oven until cheese is melty and the turkey has warmed through. Top with cut out eggs and enjoy!
Notes
How to Store and Reheat: Wrap each sandwich individually in aluminum foil. Place sandwiches in a freezer bag. Freeze for up to one month. To reheat, remove sandwich from foil. Place on a microwave safe plate that's been lined with a paper towel. Heat until egg has been warmed through and cheese is melty, about 60 to 90 seconds.Credit: Show Me The Yummy