Remove the baking pan from the oven and use the oil to line the pan to prevent sticking. Add the eggs, spinach, tomatoes, chili, mushrooms. Make sure all the mixture is evenly spread throughout the pan. Now grind a little black pepper or cayenne pepper over the top for seasoning. Place back into the oven and cook for 15 minutes. (Keep an eye on this for the first time as all ovens are a little bit different).