Butterfly the sausages (slice lengthwise, leaving them attached along one side). Spread them out flat in a large frying pan. Cook over medium heat for 15 minutes, turning once, until the sausages are browned and cooked through. Remove from frying pan and set aside.
Place the beef mince, olive oil, onion and garlic in the frying pan then cook, stirring continuously, over medium heat for until the onion is translucent and the beef is browned and crumbly, about 10 minutes. Drain all but 2 tablespoons of fat. Stir in the tomatoes, tomato puree, salt, pepper, basil, oregano and bay leaf. Simmer uncovered over low heat for 1 hour, stirring occasionally, until the flavours have blended. Remove the bay leaf.
Preheat the oven to 180 degrees C. Bring a large saucepan of lightly salted water to a boil, drop in the pasta and cook for 8 to 10 minutes, stirring occasionally, until tender. Drain the pasta then mix it into the sauce.
Place servings of hot pasta with sauce on oven-safe plates, place a cooked, opened sausage over each serving then sprinkle with Parmesan cheese. Place plates in the preheated oven for 5 to 10 minutes, until the cheese has melted and begun to brown.