Preheat oven to 425°. Peel the squash, trim off the ends, and cut in half lengthwise. Use a spoon to remove the seeds.
Cut squash into one inch cubes and place in a large bowl. Add the flour and toss to coat the squash evenly. Add the garlic and parsley.
Coat a rimmed baking sheet with half of the olive oil and spread the squash onto the tray evenly. Drizzle the remaining olive oil over the squash. Season with salt and pepper.
Roast, stirring occasionally for about 30 minutes, or until tender.