1in a skillet cook sausage and onion over med. heat until the sausage is no longer pink, drain.
Add in tomato sauce, basil, and salt.
2in a med. bowl mix ricotta, parmesan and 2 cups mozzarella cheeses.
3into a 3 1/2-5 quart crock pot spoon 1/4 of the sausage mixture. Top with about 4 noodles break to fit.
Top with half of the cheese mixture and 1/4 of the sausage mix. top with 4 noodles remaining cheese mixture and 1/4 of the sausage mixture. Top with the remaining 4 noodles and sausage mix.
4cover, cook on low heat for 6-8 hrs ( high alt. cook 5-7)
5About 10 minutes before serving put the rest of the mozz. cheese on top, cover and let stand for about 10 min or until the cheese is melted.