1Preheat the oven to 160°C, fan 140°C, gas 3. Mix the potatoes, onions and thyme leaves together in a bowl and season. Roughly layer the potatoes and onions in a roasting tray and put the lamb on top, skin-side up.
2Use a knife to pierce the lamb all over, then put a clove of garlic into each hole. Pour over the chicken stock. Put the baking tray in the oven and roast the lamb for 4-5 hours, until the lamb is tender and the potatoes are cooked through.
This recipe is great to stick in the oven on a Sunday morning, then go and walk the dogs and call in at the pub for a couple. When you get home the house smells amazing – and lunch is ready. I think I can safely call it the ultimate family lunch!
3Remove the tray from the oven, cover it with foil and leave the lamb to rest for 20 minutes before carving.