1. Heat the oven to 220C/425F/gas mark 7.
  2. Strip the leaves off the rosemary and set aside. Scatter the twigs in a roasting tray. Open out the lamb, pat it dry and lay it on top of the rosemary twigs.
  3. Now put all the remaining ingredients into a food processor with the rosemary leaves and blitz into a paste. Spread the paste over the lamb.
  4. Roast it in the oven for 40 minutes, or until the lamb is still nicely pink inside. Set it aside to rest for at least 15 minutes before serving.


  • Deglaze the roasting tray with 200ml of wine, stock or water to make a luscious yet simple gravy.
  • Feel free to substitute black olives for the anchovies – say about 18 large ones.
  • If you want more of an all-in-one supper dish, chop up some red peppers and a bulb or two of fennel and scatter them in the base of the roasting tray. Drizzle with a little olive oil and moisten with a splash of stock, wine or water, then lay the lamb on top and roast as above.