Preheat oven to 400°F (200°C). Using sharp knife, halve Cornish hen through backbone. Place in small roasting pan. Whisk together garlic, oil, thyme, salt and pepper; rub over Cornish hen halves. Roast for 40 to 45 minutes or until golden brown and internal temperature reads 165°F (74°C) when instant-read thermometer is inserted into the thigh. Let stand for 5 minutes before serving.
Meanwhile, add radicchio, garlic, Parmesan, vinegar, honey, salt and pepper to food processor; pulse until combined. Add oil; pulse until almost smooth. Set aside. (Pesto can be covered and refrigerated for up to 1 day.)
Cook pasta according to package directions. Drain, reserving 1/4 cup (60 mL) of the cooking liquid. Toss pasta and cooking liquid with Radicchio Pesto. Divide evenly between two plates. Top with portion of Cornish hen. Garnish with Parmesan, and parsley, if using.
Use a vegetable peeler to shave Parmesan into strands for an elegant garnish.