Heat olive oil in a large Dutch oven or pot over medium-high heat. Add the Italian sausage and cook until browned, breaking it apart with a spoon. Add the diced onion and cook until softened, about 5 minutes. Stir in the minced garlic, dried oregano, and red pepper flakes and cook for another minute until fragrant.

Pour in the crushed tomatoes, tomato sauce, and chicken broth. Stir everything together, scraping up any browned bits from the bottom of the pot. Bring the mixture to a boil, then reduce the heat to a simmer.

Add the broken lasagna noodles to the pot. Let the soup simmer for 10-12 minutes, or until the noodles are al dente, stirring occasionally to prevent them from sticking.

Stir in the heavy cream and season with salt and black pepper to taste.

While the soup simmers, combine the ricotta cheese, mozzarella cheese, Parmesan cheese, and fresh parsley in a small bowl. Mix until well combined.

Ladle the hot Lasagna Soup into bowls. Top each serving with a generous dollop of the cheesy ricotta mixture. Garnish with more fresh parsley if desired.