Preheat the oven to 400ºF. Cut the ends off the delicata squash, then slice it open length-wise.
Use a spoon to scrape out the seeds, then slice the squash into ½-inch wide slices.
Place the sliced squash on a parchment-lined baking sheet. Drizzle with olive oil, then sprinkle the salt, garlic powder, and pepper over top. Toss the squash until it is fully coated in oil and spices. Make sure it is spread out over the baking sheet in an even layer.
Transfer the baking sheet to the oven and roast for 20 minutes. After 20 minutes, flip the squash pieces over. Roast for an additional 10-15* minutes, or until browned to your liking.
Taste the squash and adjust the salt or pepper to your liking. Serve warm.