Preheat the oven to 200°C. Lightly coat a pan with cooking spray or a teaspoon of olive oil. Combine the mint jam, lemon juice and fresh mint in a small saucepan. Stir over medium heat for about 5 minutes or until the jam melts. Remove from the heat and set aside.
Meanwhile, slash the lamb in half horizontally, cutting three-quarters of the way through. Open and spread flat like a book. Pound the meat with a rolling pin to about 2.5cm (1in) thickness.
Brush about 2 tablespoons of the mint sauce over the lamb, then sprinkle with the garlic, rosemary and pepper. Squeeze the juice from one lemon half over the lamb. Roll up the lamb from one wide side and tie with kitchen string, in both directions. Transfer to the roasting tin, seam-side down. Squeeze the remaining lemon half over the lamb and pour on the wine.
Roast for about 50 minutes or until cooked to your taste. Leave to rest for 10 minutes. Meanwhile, reheat the remaining mint sauce. Remove the strings from the lamb and cut into 1cm (½in) slices. Serve with the mint sauce.
Some more ideas
*Although lamb and mint sauce is a traditional pairing, you can prepare a 1kg joint of lean boneless beef or pork in the same way. *Serve this dish with steamed asparagus and potatoes.
Lamb is a rich-tasting meat. Over the years it has become much leaner due to consumer demand for less fatty meats. While still not as lean as pork or poultry are, lamb is very flavourful and so can often be served in smaller portions.