Cook pasta according to package directions until al dente. Reserve 1/2 cup pasta water. Transfer pasta to baking dish. While pasta is cooking, cook sliced sausage pieces in the olive oil heated in skillet. When sausage has browned on each side add onions, garlic and mushrooms, cook until onions are translucent and mushrooms are golden. Add reserved pasta water and cream to skillet bring to a boil turn down heat and let simmer for 4 minutes. Pour over pasta and add Parmesan cheese and half of mozzarella cheese stir until combined, Top with remaining mozzarella and 1/4 cup Cheddar Cheese. Bake for 25-30 mins until hot and bubbly and cheese has melted. Serve hot.