From Annabel Langbein’s book ‘Simple Pleasures’.
Bone in leg of lamb. Cook at 150 degrees for 30 minutes (if frozen).
Slice potato and kumera 1.5cm width and lay overlapping each other on bottom of roasting tray. Season with salt and pepper and add 1 cup of chicken stock. Put leg on top and roast for another 30 minutes at 180 degrees.
After 1 hour cover the leg in the herb crust and bake for another 60 – 75 minutes until cooked medium rare.