Method

1. Preheat the oven to 220C/gas 8

2. Place the lamb on a chopping board and make incisions over the joint with a sharp knife. Insert slivers of garlic into the cuts.

3. Heat the dripping in a roasting tin in the oven until smoking hot. Place the lamb in the tin and roast for 30 minutes.

4. Turn the heat down to 170C/gas 3 and continue roasting for about 1 hour 20 minutes. Pierce the meat with a skewer to test if it's done. If the juices run a pale pink, it's ready. While the lamb is roasting, make the mint sauce.

5. For the mint sauce, finely chop the mint leaves along with a teaspoon of the measured sugar - this helps fix the colour. Place the chopped mint in a heatproof jug and pour over the boiling water. Stir in the remaining sugar, and sharpen with enough vinegar to give a pleasant tang,

6. Take the lamb out of the oven and remove from the roasting tin. Leave to stand for about 15 minutes on a chopping board while you make the gravy. This standing time gives the meat time to relax and develop its flavour.

7. For the gravy, pour off any extra oil from the roasting tin, leaving back a tablespoon or so in the tin. Place the roasting tin over a low heat, add the onions, and cook until softened. If it looks like catching on the bottom of the tin, add a dash of red wine and scrape well with a metal spoon to lift up any meaty sediment - this has the most flavour and adds a rich flavour to the finished gravy.

8. Once the onions are soft, pour in the remainder of the wine and add the stock and redcurrant jelly. Bring to a boil over a medium heat and cook down until reduced by one third.

9. Mix the cornflour with 1 tablespoon of water until it resembles a smooth paste. Add a ladleful of the hot gravy into the cornflour mixture and stir to mix before returning to the pan. Stir, over a moderate heat, until the gravy has thickened. Taste for seasoning and keep warm until ready to serve.

10. Carve the lamb into medium-thick slices using a sharp knife, and serve with the gravy and mint sauce. Accompany with roast potatoes and a green vegetable such as fresh peas.