Slow Cooker Lasagna

1 lb uncooked lean ground beef (7% fat)
1 small onion,chopped
1 medium garlic clove ,minced
28oz canned crushed tomatoes
15oz canned tomato sauce
1t table salt
1t dried oregano
1/2t dried basil
1/4t crushed red pepper flakes, or to taste
1 Cup part-skim ricotta sheese
1 1/2 Cup part-skim mozzarella cheese, shredded, divided
6 items dry lasagna noodles, no-cook
1/2Cup shredded Parmesan cheese, strong flavored like Romano or Parmigiano Reggiano

Heat a large nonstick skillet over medium-high heat. Add beef, onion and garlic; cook, stirring frequently, breaking up meat with a wooden spoon as it cooks, about 5-7 minutes. Stir in crushed tomatoes,tomato sauce, salt, oregano, basil and red pepper flakes; simmer 5 minutes to allow flavors to blend.

Meanwhile , in a medium bowl, stir together ricotta cheese and 1 Cup mozzarella cheese.

Spoon 1/3 of beef mixture into a 5-quart slow cooker. Break 3 lasagna sheets in half and arrange over beef mixture; top with half of ricotta mixture. Repeat with another layer and finish with remaining 1/3 beef mixture.

Cover slow cooker and cook on low setting for 4 to 6 hours. Remove cover; turn off heat and season to taste, if desired.

In a small bowl, combine remaining 1/2 Cup mozzarella cheese and Parmesan cheese; sprinkle over beef mixture. Cover and set aside until cheese melts and lasagna firms up, about 10 minutes. Yields 1/6th of dish per serving.