Brown ground beef and onion in skillet . Lightly salt and pepper. Drain.
Place the beef mixture with the 3 tomato ingredients and bay leaf into the Slow cooker.
Cover and set on low. This should cook 6 to 8 hours and thicken into a nice sauce.
Cook noodles, drain and place in cool water.
Remove bay leaf and begin layering in your 13 x 9 lightlly greased pan.
1st layer is the sauce , 2nd (4 noodles ), 3rd sauce, 4th(4 noodles,) 5th sauce, 6th (4 noodles).
Last layer is sauce. Top with package of Mozarella.
Cover tightly with foil and bake at 350 degrees for 1 hour. Let stand for 5 minutes before serving.