Roast Duck with Orange Sauce

Rinse duck, pat dry, season with salt and pepper inside and out and season with thyme inside. Place into a large roasting pan and roast in preheated oven at 180°C (approximately 350°F) for about 1.5-2 hours. Gradually add broth. Peel oranges, removing as much pith as possible. Fillet and collect all resulting juice. If necessary, add more orange juice to make 250 ml in total (approximately 1 cup). Remove duck form the oven. Reduce cooking juices and strain through a sieve. Add orange juice and Grand Marnier and reduce slightly. Add orange fillets and season with salt and pepper.