Preheat the oven to 400. Slice the squash in half lengthwise and scape out the seeds and fibrous flesh with a spoon. Rub the flesh with the olive oil, then sprinkle with salt and a pepper.
Place the squash cut side down onto a sheet pan and then place in the oven on a rack in the lower third. Roast until the exterior is golden brown and the skin can be pierced with a fork, about 40 minutes.
Remove the squash from the oven and carefully flip over. Using the tines of a fork, carefully rake the flesh, starting from the edges and moving inward, into long strands. Scrape the raked flesh from the skin with the fork, gently toss to incorporate the seasoning, and serve immediately.