2.Trim leeks; cut into quarters lengthways. Combine leek and oil in a large baking dish; season. Cover dish with foil; roast 15 minutes.
3.Meanwhile, combine butter, rind, basil and garlic in a small bowl. Using your fingers, make a pocket between the chicken breasts and skin; push butter mixture under skin. Season.
4.Place chicken on top of leeks. Roast, uncovered, for 20 minutes or until chicken is cooked, spoon pan juices over chicken after 10 minutes.
Chicken breast supremes have their skin intact. They are single boneless breasts with the wing bone attached. Small chickens (500g/1 pound) make a wonderful substitute for the chicken breast supremes used in this recipe. Allow one chicken per person and cook for roughly double the time.