Slice both ends off of the squash. Stand your squash up and use the body of your knife to slice through the squash. I find rocking the knife back and forth is the best way to get the job done (see video for a demo).
Remove seeds and stringy membranes from each squash half and season with a drizzle of olive oil, salt, pepper, and garlic powder.
Place halves, skin side up, on a rimmed baking sheet lined with parchment paper. Roast for 35-40 minutes or until tender.
Allow squash to cool down and then use a fork to scrape the spaghetti strands from the skin. Enjoy!