Preheat the oven to 400°F (200°C).
Cut the spaghetti squash in half lengthwise and scoop out the seeds.
Drizzle the inside of the squash with olive oil and season with salt and pepper.
Place the squash halves, cut side down, on a baking sheet and roast in the preheated oven for about 40-45 minutes, or until tender.
While the squash is roasting, heat the remaining olive oil in a pan over medium heat.
Add the minced garlic to the pan and sauté until fragrant, about 2 minutes.
Once the squash is done roasting, let it cool slightly before using a fork to scrape out the flesh into spaghetti-like strands.
Add the scraped squash to the pan with the sautéed garlic and toss to combine.
Stir in the grated Parmesan cheese and chopped parsley.
Season with additional salt and pepper if needed, and serve immediately.