Cook the pasta according to packet instructions.
Meanwhile, heat the oil in a large frying pan over medium heat. Add the onions, mushrooms and squash and fry, stirring, for 10-15 minutes, or until soft and the mushrooms release their juices. Add a splash of water if it starts to stick.
Add the garlic, butter and sage and fry for another 2 minutes, then season to taste.
Stir in the ¼ cup of the pasta cooking water, cream and parmesan cheese and season with salt and pepper.
Serve over the cooked pasta noodles.
