Preheat Oven to 350 and grease a 9x11 Casserole Dish (cooking spray is fine)
Saute Diced Onions & Potatoes on stove top in Olive Oil. Add 1 teaspon Salt and Pepper while sauteing.
Beat eggs in mixing bowl with 1/2 teaspoon salt and pepper.
In your casserole dish pour the onions and potatoes in and sprinkle the sausage.
Drizzle the beaten eggs over the veggies and sausage. Cover with cheese. Cover with a casserole glass lid or aluminium foil. Cook for 40 minutes or until eggs are cooked, not runny.