Preheat oven to 375° F.
Cut squash in half lengthwise with a sharp kitchen knife.
Scoop out the seeds with a spoon or scoop. Discard seeds or roast separately. (To roast the seeds, see notes below.) Place squash halves on the foil-lined sheet pan and coat with olive oil. Season with salt and pepper. Rub oil to coat entire flesh of squash, and skin.
Place the squash face down and pour ½ cup of water into the bottom of the pan.
Roast the squash in the oven, uncovered, for about 40-45 minutes, or until soft and it can be pierced with a fork or knife. Periodically check on the squash to make sure the water hasn't evaporated, and add more as needed. Also, make sure it isn't burning or becoming overcooked.
Once the squash is cooked, remove from the oven. Allow squash to cool until it may be handled safely.
If using for a purée or mash, scoop out the flesh of the squash from the skins.
If cubing, remove the skin. Lay the squash flesh side down on a cutting board and gently shave/slice off the skin, making sure not to take off too much of the flesh. Flip over, run knife along the top edge to ensure no skin is remaining.
Once peeled, the squash may be cubed. Lay flat side down, slice with a sharp knife horizontally. Then, cut down lengthwise, then widthwise, creating cubed squash.
Serve mashed, use in a soup as a purée or cubed, add to side dish or salad, or enjoy on it's own! Enjoy!