Heat olive oil in a large pot over medium-high heat. Add the Italian sausage and diced onion, breaking up the sausage into crumbles as it cooks. Cook for 6-8 minutes until browned and onion is translucent. Drain excess fat.

Stir in minced garlic and cook for 1 minute until fragrant.

Add beef broth, marinara sauce, tomato sauce, oregano, basil, and red pepper flakes (if using). Stir and bring to a gentle simmer for about 3-4 minutes.

Break lasagna noodles into 2-3 inch pieces and add to the simmering soup. Cook for about 10 minutes, stirring occasionally, until noodles are al dente.

While noodles are cooking, mix ricotta and parmesan cheese in a small bowl and set aside.

Once noodles are done, stir in fresh chopped basil and season with salt and pepper. Serve hot, topped with the ricotta mixture.