Place a large Dutch oven over medium-high heat and brown the Italian sausage, using a wooden spoon to break the meat into small crumbles until no longer pink.
Add diced onions to the pot and sauté for 5 minutes until translucent, then add minced garlic and cook for an additional 60 seconds.
Incorporate tomato paste, oregano, and basil into the meat mixture, stirring constantly for 2 minutes to caramelize the paste.
Deglaze the pot by adding marinara sauce and chicken broth, stirring to scrape any browned bits from the bottom.
Bring the liquid to a rolling boil, then introduce the broken lasagna noodles.
Reduce heat to medium-low and simmer uncovered for 12 minutes, or until the noodles reach al dente texture.
While the soup simmers, whisk together ricotta, Parmesan, and salt in a small bowl.
Remove soup from heat, ladle into bowls, and top each serving with a dollop of the ricotta mixture, shredded mozzarella, and fresh parsley.