Cook the pasta and drain it; cook the sausage and drain it; shred the mozzarella cheese.
Make the filling by combining the ricotta cheese, Italian seasoning, parmesan cheese, garlic powder, salt, and egg.
Spread some of the sauce on the bottom of a 13x9 pan and cover the bottom.
Layer half the pasta over the sauce.
Spread half the filling over the pasta, then sprinkle half of the sausage on top of the filling.
Spread half of the remaining sauce over the sausage.
Sprinkle half of the mozzarella on top of the sauce, then layer the remaining pasta over the top of the cheese.
Spread the rest of the filling over the pasta, then sprinkle on the rest of the sausage.
Spread the rest of the sauce on top of that.
Sprinkle with the rest of the mozzarella, then bake at 350 degrees for 35-45 minutes, until cheese on top starts to brown.