Preheat oven to 200°C regular bake. Grease a large baking or lasagne dish.
Peel and desired the pumpkin and cut into 5cm pieces. Add to the prepared dish with the olive oil, rosemary and salt and pepper. Toss to combine and roast in the oven for 20 minutes.
Cut each sausage into six pieces. Heat 1 tablespoon oil in a frying pan over a high heat, then brown the sausage pieces - they'll turn into rough little meatballs. Set aside.
Add the olive oil and the onion to the same pan. Cook for 5 minutes until soft. Add the garlic, courgette (or spinach) and oregano. Cook, stirring, for another few minutes. Add the sausage, tomatoes, stock, red wine (if using), tomato paste and sugar, turn up the heat and simmer rapidly for 10-15 minutes or until reduced to a thick sauce.
While the sauce is cooking, cook the pasta according to the packet directions until al dente (slightly firm to the bite). Drain and set aside.
Arrange the sausage, Pumpkin and pasta in the baking dish and pour over the sausagey sauce. Stir roughly to combine. Spread the crème fraìche over the top. Sprinkle with the cheddar or mozzarella and parmesan, and bake in the oven for 20 minutes until golden and bubbling on top. You can turn the oven to grill to give it a little more colour at the very end.
Sprinkle with parsley and serve with a green salad or your choice of vegetables.