In a large pot or Dutch oven, heat the oil over medium-high heat. Add the onions and cook for about 4 minutes or until the onions start to soften. Add the sausage and ground beef and cook, stirring occasionally until browned. Stir in the minced garlic and sauté for about a minute. Drain any excess fat if needed.

Stir in the diced tomatoes, crushed tomatoes, tomato paste and broth. Stir in the Italian seasoning and dried oregano. Season with salt and ground black pepper to taste.

Bring to a boil, then reduce the heat to low. Cover and simmer for 20 minutes.

While the soup simmers, cook the lasagna noodles in a separate pot according to package directions until al dente (you want the pasta tender but not overly soft as it will be added to the soup).

In a mixing bowl, stir together the shredded mozzarella, grated Parmesan and ricotta cheese. Set aside.