Preheat oven to 350 degrees F.
Reserve half of the squash for another use. Place 1 spaghetti squash half, cut side down, on a nonstick baking sheet. Roast for 30 to 40 minutes or until tender. Remove flesh from skin with a fork. Toss with the roasted garlic pesto. Top with Parmesan and serve warm.
Preheat oven to 375 degrees F. Cut tops off garlic. Lightly spray each with cooking oil spray. Wrap in aluminum foil and roast for 1 hour. Let cool before handling. Squeeze pulp from garlic into a food processor. Add basil and pine nuts and pulse until smooth.