Slow-roasted lamb with spring onion mash and pistou recipe | Sainsbury`s Magazine (2024)

A magnificent relaxed sharing platter that just bursts with flavour

Tom Booton

Tom is head chef at The Grill at The Dorchester in London. Just 27 years old, he is the youngest chef to have held the position there and has won wide acclaim for the way he has modernised one of the captial's most established restaurants

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1. You’ll need to brine the lamb on Friday night: bring 2 litres of water to boil in a large pan then take off the heat and add the salt, 3 sprigs of rosemary, the black peppercorns and half the head of garlic. Leave to cool, add the lamb shoulder, cover and chill overnight.
2. On Saturday afternoon, preheat the oven to 170°C, fan 150°C, gas 31⁄2. Remove the lamb from the brine, rinse and dry well, putting the garlic and rosemary from the brine into a medium roasting tin. With a small knife, carefully pierce the lamb shoulder all over and tuck in slices of garlic, small sprigs of rosemary and mint. Place the lamb in the roasting tin, add the other half head of garlic (keep back 1 small clove for the pistou) and pour in two-thirds of the stock. Cover the roasting tin tightly with foil and place in the oven for 3-31⁄2 hours until tender. Check after 2 hours, and add the rest of the stock to the tin.
3. Turn the oven up to 200°C, fan 180°C, gas 6, remove the foil and return the lamb to the oven for 20 minutes to get a beautiful roasted colour and flavour.
4. Cut all the potatoes the same size, cover with cold water in a saucepan and add the salt. Cook on a medium heat for 20-25 minutes, or until soft.
5. For the pistou, pick the leaves from the mint and parsley. Place in a food processor with the rest of the pistou ingredients and a pinch of salt. Pulse to a coarse paste.
6. When the lamb is ready, remove the meat from the roasting tray and spoon some of the pistou over the joint. Cover loosely with foil and rest for 20 minutes before eating. Spoon off the fat from the roasting tin then stir the red wine into the juices. Bring to the boil and start to reduce (tip into a saucepan first if you prefer). Mix the cornflour with a little cold water until smooth and add this into the liquid to make a quick gravy. If the gravy is still quite thin, bubble to reduce to the desired consistency.
7. Drain the potatoes into a colander and leave to steam for 4-5 minutes (this is very important, but don’t let them go cold). In the same pan, add the milk and butter and bring to a boil, almost starting to reduce the milk and butter to make a beautiful emulsion. After a few minutes turn the heat off, add the potatoes and mash until they are as smooth as possible. Check for seasoning. If you would like your mash even smoother, pass the mash through a fine sieve, into a clean pan. Stir in the crème fraiche and mustard, cover the pan and keep warm. Stir in the spring onions just before serving.

   This recipe makes extra mash - remember to set aside 350g of mash for tomorrow’s bubble and squeak cakes.

8. Bring a pan of seasoned water to a strong boil, cook the beans for 3 minutes or until just tender but still with a crunch. Drain well and toss with a couple of spoonfuls of pistou. Strain the gravy into a warmed jug. Shred the lamb and serve with the beans, mash and gravy, and extra pistou to spoon over if you wish.