In a big pot on medium-low heat, add butter. Sauté onion until translucent and add garlic. Once garlic is fragrant, add ground beef.
Season ground beef and cook until browned. Add tomato paste, mix with beef, and cook for 3-4 minutes before adding marinara sauce.
Once marinara comes to a simmer, add beef broth. Bring heat to medium-high. Once meat sauce comes to boil, add lasagna pieces. Cover and cook for 6-7 minutes.
Add heavy cream with Parmesan and mozzarella cheese. Season again with a little less seasoning than before. Mix and add fresh parsley and fresh basil. Cover and simmer on low for 5 minutes.
For ricotta mixture: in a small bowl, combine 2 parts ricotta, 1 part mozzarella, and Parmesan. Add fresh basil and mix.
Serve lasagna soup with ricotta mixture and garnish with parsley and Parmesan.
