Preheat oven to 375°F.

Microwave butternut squash on high for 3-4 minutes to soften it enough to make cutting easier.

Cut squash in half, remove seeds and guts and discard. Place squash halves on a sheet pan and drizzle generously with olive oil and add salt & pepper to your liking. Flip squash over (so the flat side is down) and add the water to the sheet pan.

Roast in oven for 40-50 minutes, checking after 30 minutes to ensure squash isn't burning. When you can easily pierce the squash with a knife and most of the water has evaporated, remove and let cool. When you can safely handle it, scoop flesh out with a spoon or ice cream scoop. Mash with a fork or a potato masher and enjoy.