Step 1: Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Step 2: Slice the ends off the spaghetti squash, then stand it upright and carefully cut it in half lengthwise (or crosswise for longer strands).
Step 3: Use a large spoon to scoop out the seeds and stringy pulp from the center of both halves.
Step 4: Drizzle the interior of the squash with olive oil and sprinkle with salt, pepper, and garlic powder, rubbing it in to coat evenly.
Step 5: Place the squash halves cut-side down on the prepared baking sheet.
Step 6: Roast for 40-50 minutes, or until the skin is easily pierced with a fork and the edges are starting to brown.
Step 7: Remove from the oven and let cool for 5-10 minutes. Use a fork to scrape the flesh, pulling it away from the skin to create spaghetti-like strands.