Pre heat your oven to 375 degrees. Spray 8X13 casserole dish with cooking spray.
Cook your pasta according to directions and drain.
In large bowl, mix ricotta cheese, egg, garlic salt, Italian seasoning and pepper until well combined. Add the pasta and mix well.
Saute your sausage (if uncooked) or brown pre-cooked sausage.
Put half of your tomato sauce on bottom of casserole dish, then spread half of the pasta mixture on top of it, then layer half of the suasage. Sprinkle half of the mozzarella cheese next. Repeat the tomato sauce, pasta mixture, rest of sausage, mozzarella cheese and finish by sprinkling the parmesan cheese on top.
Cover the casserole with tin foil and bake for 30 minutes, then remove foil and broil just for a minute or two,browning the cheese on top.