Leg of lamb is traditionally roasted in a hot oven (190˚C–220˚C) though it can also be slow cooked at lower temperatures for much longer. Lamb leg steaks are widely available for pan-frying and grilling and diced leg can be used for stews, tagines and pies.
When cooking a leg of lamb whole, don’t remove any excess fat – it adds flavour and helps keep the meat tender. The fat will render down during cooking; drain it from the roasting tray and whisk it into your gravy for an extra boost of lamb flavour.
It is important to let the meat come to room temperature before beginning to ensure it will cook through evenly. It is also imperative to let the meat rest after cooking, 20 minutes is sufficient. Wrap the leg in tin foil to prevent it from getting too cold.
Use a meat thermometer to test whether your meat is cooked or not; it’s not essential but will help determine to what stage the lamb is cooked, from rare (48–54˚C) to medium-rare (55–59 °C) to medium (60–66˚C) to well done (67–74˚C) and give a more consistent result. Roast lamb should be served pink in the middle. If overcooked, it is dry, chewy and unpleasant.
To decrease the cooking time, you can ask your butcher to remove the bone running down the middle of the leg, a technique known as butterflying. This is ideal for cooking on a barbecue. Try marinating the meat before cooking as Robert Thompson does in his recipe for Chargrilled leg of lamb with salsa verde and roasted beetroot.
Traditional flavour pairings for roast lamb are mint, rosemary, redcurrants, anchovies and garlic – see Andrew MacKenzie’s Roast leg of Welsh lamb with rosemary and anchovy or Shaun Rankin’s Roast leg of lamb with honey and minted Jersey Royals. For more exotic results, try Andy Waters’ Moroccan lamb with fluffy cous cous or Anna Hansen’s Roast Baharat and lemon marinated Welsh lamb with sweet potato and fresh coriander.