Heat olive oil in a large pot or Dutch oven over medium-high heat. Add the Italian sausage and break it up with a wooden spoon as it cooks. Brown for 5 to 7 minutes until no pink remains and golden color forms on the meat.

Add the diced onion and cook for about 5 minutes, stirring occasionally, until softened and translucent. Stir in the minced garlic and cook for one more minute until fragrant. Watch closely so the garlic does not burn.

Pour in the chicken broth, heavy cream, and tomato sauce. Stir in the oregano, basil, and red pepper flakes if using. Bring to a gentle simmer over medium heat. Do not allow a hard boil once cream is added.

Add the broken lasagna noodle pieces and cook for 8 to 10 minutes, stirring every couple of minutes to prevent sticking. Pull them just before fully done as they continue cooking in the hot broth.

Reduce heat to low. Stir in half the mozzarella and all of the Parmesan until melted and smooth. Taste and adjust salt if needed.

Ladle into bowls and top with the remaining mozzarella and fresh basil. Serve immediately for the best texture.