Spaghetti squash are very hard and therefore hard to cut through. Place the squash perpendicular to you with the stem at one end and the bottom at the other. Make sure it is sitting as flat as possible. Place your largest knife running lengthwise along the squash. Do not try to cut it yet, just place the knife there. Hold the knife firmly and using the heel of your other hand, pound down on the top of the knife to force it into the squash. You are just trying to cut a slit in the squash, so don’t worry if it didn’t go very deep. Now take the knife and insert the tip into the squash near the middle and bring the handle down to the counter. You should have cut half of the squash in two. Rotate the squash, insert the tip into the slit with the blade facing the uncut half, and bring the handle down to the counter again. You will now have the squash cut into two halves running the length of the squash.
Scoop out the seeds and pulp (the seeds are very good roasted). Place the two halves of squash flesh side down in a rimmed baking pan. Add 2 cups water to the pan and place in the oven. Bake for 40 minutes or until a knife inserted in the flesh reaches all the way to the skin. Remove from the oven and cool.
When cool enough to handle, move squash to clean surface and use a fork to scrape out the flesh. It will resemble yellow spaghetti. The fibers actually run around the squash, not the length of it, so you will get the longest “spaghetti” if you scrape from side to side not top to bottom.
One Last Thing
If you're short on time, just place your squash in a baking dish with water and put it in the microwave for 10 minutes.