Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Add the Italian sausage and cook for 5-7 minutes, breaking it up with a spoon, until browned. Add the chopped onion and cook for 4-5 minutes until softened. Stir in the minced garlic, dried oregano, dried basil, and red pepper flakes, and cook for 1 minute more until fragrant.

Push the sausage mixture to one side of the pot. Add the tomato paste to the empty space and cook, stirring constantly, for 1-2 minutes until it darkens in color. Stir the paste into the sausage mixture.

Pour in the fire-roasted tomatoes (with their juices) and the broth. Scrape up any browned bits from the bottom of the pot. Bring the mixture to a simmer.

Add the broken lasagna noodles to the simmering soup, pushing them down to submerge them. Reduce the heat to maintain a gentle simmer, cover, and cook for 10-15 minutes, or until the pasta is al dente, stirring occasionally to prevent sticking.

While the soup simmers, prepare the ricotta topping. In a small bowl, mix together the ricotta cheese, 1/4 cup of the grated Parmesan cheese, a pinch of salt, and a pinch of black pepper. Set aside.

Once the pasta is tender, reduce the heat to low. Slowly stir in the heavy cream until fully incorporated. Add the fresh spinach and stir until it has just wilted, about 1-2 minutes.

Taste the soup and season generously with salt and black pepper until the flavors are balanced.

To serve, ladle the hot soup into bowls. Top each bowl with a generous dollop of the seasoned ricotta mixture, a sprinkle of shredded mozzarella, the remaining Parmesan cheese, and fresh torn basil leaves.