According to British chef Heston, the secret of cooking a juicy roast chicken is to soak the chicken in a salty water the night before. The amount of salt you need to make salty water is 60 gram of salt per kilogram chicken.

Take the chicken out of the salty water, and drain it throughly. Rub some butter on the skin of the chicken. Stuff some rosemary and a whole lemon inside the chicken. Put the stuffed chicken in a preheated oven at temperature of 90^oC for one and half hour. Once its cooked, turn the temperature up to 250^oC for 10 minutes or so to get the skin crispy.