You have to turn to Nigel Slater's lemon and thyme recipe in Real Food. Turn your oven up high for first 20 mins to get crackling skin (then lower for the rest of the cooking). First, butter liberally, add plenty of salt, pepper and chopped thyme, a squeeze of lemon all over and the left-over lemon gets stuffed up its tush. Make sure it's fully cooked by sticking a skewer in the leg - the liquid that comes out must be clear, not pink. Voila!