With a large sharp knife, pierce whole Winter Squash near the stem, and insert the knife. Rock back and forth, cutting your way around the entire squash cutting all but the stem. Remove knife and break squash in half. Use knife to remove remaining stem.
Use a spoon to discard seeds. If desired, you can remove pulp from seeds and roast them too.
Rub the flesh of the squash with the olive oil. Place face down on a rimmed baking sheet. Bake, face down, in oven for 45 minutes to an hour. You'll know when the squash is done based on how easily a butter knife inserts into the flesh of the squash, and also based on the wonderful smell. When done, remove from oven and allow squash to cool on baking sheet.
When cool enough to handle, cut squash into sections and remove skin.
At this point you can serve the roasted squash as a side dish, cube it for a recipe, or puree it.
To puree the squash, place peeled squash sections in a food processor. It is very thick so it occasionally needs to be re-positioned in the processor if it appears to not be thoroughly mixing. Pureed squash can be frozen in an air tight container or plastic freezer bag for future use.
Video
Notes
Cooking tips:
Because cutting a large, hard, whole squash can be challenging, you can always throw the whole thing in the oven for about 15 minutes to allow it to soften a bit before cutting it.
You can add the roasted squash to the food processor. If the mixture is too thick, you can thin it with some water or olive oil. Occasionally I have to use a scraper to push the chunks down, but otherwise it blends up nicely.
Butternut squash can be especially difficult to cut when raw. An easier method is to first cut the top off right where the squash transitions from thin to fat. Then place the flat cut side down on the cutting board and cut each of those halves in half. This would result in four chunks instead of two.
The smaller the squash and thinner the flesh, the less time it will take to roast. Just keep an eye on it and you'll know when you have perfectly roasted squash when it smells wonderful, starts to brown, and a fork or butter knife can easily go into the flesh.