Heat olive oil in a large pot over medium heat. Add diced onion and sauté for 3-4 minutes until soft. Stir in minced garlic and cook for an additional minute.

Add Italian sausage, breaking it into smaller pieces. Cook for 5-7 minutes until browned and fully cooked. Drain excess fat if necessary.

Pour in crushed tomatoes and chicken broth. Add dried basil, oregano, red pepper flakes, salt, and pepper. Stir and bring to a boil.

Add broken lasagna noodles, stir to submerge, reduce heat to a simmer, and cook for 10-12 minutes, stirring occasionally.

In a small bowl, mix ricotta cheese, half of the mozzarella, and half of the Parmesan cheese. Once noodles are tender, add this mixture to the pot.

Stir gently to combine and allow to simmer for a few more minutes. Serve topped with remaining mozzarella and Parmesan cheese, and garnish with fresh basil if desired.