Peel and chop your butternut squash into bite-sized chunks.
In a soup pot or deep pan, melt the butter over a medium heat and add the diced onion and cook until soft, about 5 minutes.
Add the garlic, sage and squash and cook for 1-2 minutes. Pour over the stock, stir well, and bring to the boil.
Allow to simmer for about 15-20 minutes, until the squash is cooked and you can easily stick a fork through it.
Meanwhile, bring a a pot of salted water to boil and cook the pasta to packet instructions.
Blend the squash mixture with an immersion blender, or carefully transfer to a food processor in batches and blend until smooth.
Sir in the cream and cheese and season with salt and pepper to taste.
Drain the pasta and add to the sauce, mix well.
Serve garnished with grated cheese and some optional chopped parsley. I also like lots of cracked black pepper.
Alternatively, you can portion out the sauce to mix with smaller amounts of pasta. I like to keep portions of sauce in my freezer so I have this delicious mac and cheese to hand at all times!