heat beef, onion and garlic; cook stirring frequently, stir in crushed tomatoes, tomato sauce, salt oregano basil and red pepper flakes simmer 5 minutes, in medium bowl stir riccota cheese and 1 cup mozzaella cheese. spoon 1/3 of beef mixture in slower cookr, break 3 lasagna sheets in half and arrange over beef mixture; top with half of ricotta mixture repeat another layer and finish with remaining 1/3 beef mixture. slow cook on low setting for 4 to 6 hrs. remove cover; turn off heat and season to taste in 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