Cook the ground beef, onion, and garlic in a large skillet over medium heat until the beef is browned. Drain any excess fat.
Stir in the Italian seasoning, marinara sauce, and water. Bring the mixture to a simmer.
Add the broken lasagna noodles. Cover the skillet and cook for 15 to 20 minutes, stirring now and then, until the noodles are tender.
Stir in the spinach and cook until it wilts.
Drop spoonfuls of ricotta across the top. Sprinkle the mozzarella and Parmesan over everything. Cover and cook for 3 to 5 minutes until the cheese melts.