In a large skillet, brown the beef over medium/low heat, adding the onions and garlic about halfway through. When the beef is fully cooked and the onions and garlic are translucent and fragrant, drain the skillet and return it to the stove over heat again.
Add the crushed tomatoes (do not drain the can before adding to the skillet), tomato sauce, and beef broth to the beef. Add the spices and stir well to combine. Bring the sauce and beef mixture to a boil.
Break up the lasagna noodles into quarters or thirds. I used about 10 noodles, and mix them into the sauce so they are covered. Cook the noodles for about 10 minutes until tender, but just before they're done - add the spinach. When the noodles are done, the spinach should be perfectly wilted. Stir well to combine the noodles and spinach.
Top with scoops of ricotta cheese and serve immediately.