Cut the squash in half. If it’s very hard to cut, you can microwave it for 5 minutes.
Scoop out the seeds, and place cut side down on a baking tray lined with a silicone mat.
Cook for 30-40 minutes, or until completely soft. You will know it’s ready if you pierce it with a fork and the fork easily goes through. The time will depend on the exact size of your squash, so begin checking after 30 minutes.
Remove from the oven, and allow to cool.
Using a fork, scrape the squash to reveal the spaghetti. You can either serve it inside the peel, or remove all the spaghetti onto a plate, and mix with the sauce.