Preheat oven to 350. Heat nonstick skillet over med heat. spray with cooking spray. Add spinach and sautee until wilted, about 4 minutes. Spray a 13X9 baking dish with cooking spray. Add spinach. Set aside.
In a medium bowl, beat all 12 eggs with a fork until frothy. (You should also use a stand mixer fitted with a whisk). Pour over spinach. Sprinkle with tomatoes, green onions, and feta. Sprinkle with salt and pepper.