Slice the sausages lengthwise, leaving them attached along one side. Spread them out flat in a large skillet. Cook over medium heat for 15 minutes, turning once, until the sausages are browned and cooked through. Remove from skillet and set aside.
Place the ground beef, olive oil, onion, and garlic in the skillet, and cook and stir over medium heat for about 10 minutes, until the onion is translucent and the beef is browned and crumbly.
Drain all but 2 tablespoons of fat. Stir in the tomatoes, tomato sauce, salt, pepper, basil, oregano, and bay leaf. Simmer uncovered over low heat for 1 hour, stirring occasionally, until the flavors have blended. Remove the bay leaf.
Preheat the oven to 350 degrees. Bring a large pot of slightly salted water to a boil, drop in the pasta, and cook for 8 to 10 minutes, stirring occasionally, until tender. Drain the pasta, and mix into the sauce.
Place servings of hot pasta with the sauce on oven-safe plates, place a cooked, opened sausage over each serving, and sprinkle with Parmesan cheese. Place plates in the preheated oven for 5 to 10 minutes, until the cheese has melted and begun to brown.