Preheat oven to 400°F
Using a large, sharp knife, cut off a bit of the top and bottom to create a flat base, being careful not to cut through to the center cavity.
Slice the squash in half, so that the cut ends form a base. Scrape out the seeds.
Drizzle each squash half with olive oil (and salt and pepper, if using)
Place squash halves, cut and oiled side down (base up), on to a baking pan, perhaps lined with parchment paper for easy cleanup
Roast in the preheated 400°F oven for 40 to 50 minutes, or until fork tender
Remove from oven and let cool.