You will need
1.8kg/4lb leg of lamb
3 cloves garlic, peeled and sliced
2 sprigs rosemary
900g/2lb carrots, peeled and cut into wedges
900g/2lb potatoes, peeled and quartered
1 tbsp milk
2 tsps mint sauce
Pre-heat the oven to 200°C/390°F/Gas Mark 7.
Using a sharp knife, make small incisions in the lamb and press a garlic slice well into each.
Weigh the joint and allow 20 minutes per 1lb plus 20 minutes (add a further 20 minutes for well done), then place the lamb in a roasting tray.
Roast for 20 minutes then reduce the oven temperature to 180°C/350°F/Gas Mark 4 for the rest of the cooking time.
Forty minutes before the end of the cooking time, add the carrots and half of the potatoes to roast and colour.
Cook the rest of the potatoes in a pan of boiling, salted water for 20 minutes, then drain well and add the butter and the milk.
Mash the potatoes until creamy, stir in the mint sauce, mix well and season.
Remove the lamb from the tin and leave to rest for a few minutes, then serve the lamb with the carrots and both the roasted and mashed potatoes, and some cooked spinach if you like.