Brown the sausage in a bit of oil and let cool slightly.
Place the spaghetti squash in a large mixing bowl with the sausage, tomato sauce, eggs, and seasonings. Mix well and pour into a greased 2 QT baking dish. Bake at 400 degrees for 30-35 minutes, until firm to touch and lightly browned.
Remove dish from the oven and add your toppings–sprinkle extra meat, veggies, cheese, and whatever else directly on the casserole and make sure you add the pepperoni last so it seals in all the flavor and makes a nice little “crust” on the outside.