01 - Preheat your oven to 190°C. Grease a 9×13 inch baking dish.
02 - Heat the olive oil in a large skillet over medium heat. Add the cooked breakfast sausage, chopped onion, and bell pepper. Sauté for about 5 minutes until the vegetables are softened.
03 - Add the chopped spinach and mushrooms to the skillet and cook for another 2 minutes until the spinach is wilted. Remove from heat.
04 - In a large bowl, whisk together the eggs, milk, salt, pepper, garlic powder, and paprika.
05 - Add the shredded cheese and your choice of bread cubes, cooked potatoes or frozen hash browns to the egg mixture. Stir to combine.
06 - Add the sautéed meat and vegetables to the egg mixture, stir gently to incorporate all ingredients.
07 - Pour the mixture into the prepared baking dish and spread evenly.
08 - Bake in the preheated oven for 30-45 minutes, or until the casserole is set and golden brown.
09 - Let rest for 5-10 minutes before slicing and serving.