Preheat the oven to 400 degrees F and line a baking sheet with parchment paper.
Place the squash horizontally on a cutting board. Slice off the stem and base, creating two flat ends.
Using one of the flat ends, stand the squash upright and slice it in half from top to bottom. (Don't worry if your halves are not perfectly even, your squash will still turn out okay.)
Use a spoon to scrape out the seeds and stringy parts.
Brush both halves with olive oil on the inside and season with salt and pepper to taste.
Lay the halves cut-side down on the parchment paper-lined baking sheet.
Bake spaghetti squash for 35 to 40 minutes at 400 degrees F, until fork-tender on the inside. The outside will be golden brown and the shell gives a little when pressed.
Flip each half over so the flesh side is up.
With a fork, fluff the squash flesh to create the strands. ENJOY!