Neven's Fragrant Roasted Butterfly Leg of Lamb with Boulangère Potatoes

For the lamb: Place the garlic, lemon rind, herbs, cumin, paprika, salt, pepper and olive oil in a mini chopper and blend to a smooth paste. Using a sharp knife, make holes all over the lamb, then rub in the paste, pushing it into the holes. 

Transfer the lamb to a shallow dish (or a turkey bag) and add the lemon juice. Chill overnight to marinate. The next day, take the lamb out of the fridge about 1 hour before you want to cook it. 

Preheat the oven to 180°C/350°F/Gas Mark 4

For the boulangère potatoes: Heat the oil in a frying pan with the butter and sauté the onions and garlic for 3–4 minutes over a medium heat, until softened but not coloured. Season to taste.

Layer the potatoes, onions, garlic and thyme leaves in a large roasting tin large enough to fit the leg of lamb. Season each layer as you go and finish with an attractive overlapping layer of the potatoes. Pour over the stock and set to one side.

Remove the lamb from the marinade and place onto top of the boulangère potatoes. Place in the oven and roast for 45-50 minutes. If browning too quickly, cover with tinfoil. Remove from the oven and allow to rest for 15-20 minutes before serving.