Crockpot Lasagna

3 cans of crushed tomatoes
3 cloves garlic
2T oregano
1/2 t kosher salt
1/4 t red pepper flakes
1/4 t black pepper
2 containers of ricotta cheese
2 c grated mozzarella
1/4 c grated parmesan
12 lasagna noodles
5 oz baby spinach

Combine tomatoes, garlic, oregano, salt, red pepper and black pepper.  In separate bowl, mix ricotta, mozzarella and parmesan. 

In slow cooker spread layer of sauce.  Top with four noodles.  Spread almost a cup of sauce over noodles.  Layer with spinach and cheese mixture.  Repeat this step twice.  Top with remaining noodles, sauce and mozzarella.  Cook on low for 3-31/2 hrs.