Brown the Italian sausage in a skillet over medium heat, breaking it into crumbles. Add the onion and cook until softened, then stir in the garlic for 30 seconds. Drain any excess grease.
Transfer the sausage mixture to the crockpot.
Add the chicken broth, heavy cream, Alfredo sauce, Italian seasoning, garlic powder, onion powder, and black pepper. Stir until combined.
Cover and cook on Low for 5 to 6 hours or High for 2½ to 3 hours.
About 30 minutes before serving, stir in the broken lasagna noodles.
Cover and cook until the noodles are tender.
Stir in the mozzarella cheese, Parmesan cheese, and spinach, if using, until melted.
Serve each bowl with a spoonful of ricotta cheese and garnish with fresh basil.