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Roast Lamb with Mint Sauce

A leg of lamb studded with garlic and rosemary, roasted until pink and served with a sharp fresh mint sauce: the Christmas roast of New Zealand.
Recipe Roast Lamb with Mint Sauce
  • Difficulty Medium
  • Preparation 20 minutes
  • Cooking 1 hour and20 minutes
  • Servings for 8 people

Roast lamb with mint sauce is a whole leg of lamb studded with garlic and rosemary, roasted until browned outside and juicy and pink inside, then carved at the table and served with a sharp, sweet sauce of fresh mint, sugar and vinegar.

In New Zealand, a country shaped by sheep farming where Christmas falls in the middle of summer, many families put roast lamb on the table for Christmas lunch, often next to a glazed ham, with roast potatoes and kumara, garden peas and a pavlova to finish. Mint sauce came with the British Sunday roast and is still the Kiwi way to eat lamb.

A meat thermometer takes the guesswork out of the roast: the doneness temperatures are in the tips.

Ingredients for 8 people

  • For the lamb:
  • 1 Lamb Leg bone-in, about 2.5 kg (5 1/2 lb)
  • 4 cloves of Garlic peeled and thickly sliced
  • 4 sprigs of Rosemary fresh
  • 1 Lemon finely grated zest
  • 2 tablespoons of Olive Oil
  • Salt to taste
  • Black Pepper freshly ground, to taste
  • For the mint sauce:
  • 1 large bunch of Mint about 30 g leaves
  • 2 tablespoons of Sugar caster (superfine)
  • 1 pinch of Salt
  • 4 tablespoons of Water boiling
  • 4 tablespoons of Vinegar white
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Method

  1. Take the lamb out of the fridge 1 hour before roasting and pat it dry. With a small, sharp knife, make about 12 slits 2 cm (3/4 inch) deep all over the meaty parts of the leg. Push a slice of garlic and a small tuft of rosemary into each one, keeping one sprig of rosemary aside.
  2. Preheat the oven to 220 °C (425 °F). Finely chop the leaves of the reserved rosemary sprig and mix them with the lemon zest, the olive oil and a generous amount of salt and pepper. Rub the mixture all over the lamb and set it in a roasting tin.
  3. Roast for 15 minutes, until it starts to brown, then lower the oven to 180 °C (350 °F) and roast for about 1 hour more for medium-rare, longer for well done. Start checking with a meat thermometer after 45 minutes, in the thickest part of the leg (see the tips for the temperatures).
  4. While the lamb roasts, make the mint sauce. Strip the leaves from the mint, put them on a board with the caster sugar and the pinch of salt and chop them very finely: the sugar helps. Scrape them into a small jug, pour over the boiling water and stir until the sugar dissolves. After 5 minutes, stir in the vinegar, taste and add a little more sugar or vinegar to your liking. Leave it for at least 30 minutes.
  5. When the lamb reaches the temperature you want, move it to a board, cover it loosely with foil and let it rest for 20 to 30 minutes, so the juices settle back into the meat.
  6. Carve the lamb into slices across the grain, cutting down to the bone, then turn the leg and carve the other side. Serve it with the mint sauce and the pan juices, roast potatoes and kumara (sweet potato), and green peas. Finally, remember to download our App with exclusive content and fewer ads!

Variations and Alternatives

Malt vinegar makes a sharper, British-style mint sauce, but it contains gluten. A boneless or butterflied leg cooks faster: start checking the temperature after 40 minutes. For a slow roast, cook a lamb shoulder covered at 160 °C (325 °F) for 3 to 4 hours, until it pulls apart. To make gravy, pour off most of the fat, stir 1 tablespoon of flour into the juices in the tin, add 400 ml (1 2/3 cups) of lamb or vegetable stock and bubble until thick.

Tips

Use a meat thermometer in the thickest part of the leg, without touching the bone, and take the lamb out when it reads 55 °C (130 °F) for medium-rare, 60 °C (140 °F) for medium or 70 °C (160 °F) for well done: it rises by another 3 to 5 °C (5 to 10 °F) while it rests. Food safety agencies such as the USDA advise at least 63 °C (145 °F) after resting for whole cuts of lamb, so pinker meat is a matter of personal choice. As a guide, a 2.5 kg (5 1/2 lb) leg needs about 1 hour 15 minutes in total for medium-rare. Make the mint sauce on the day: after a few hours the mint darkens in the vinegar.

Storage

Cool leftover lamb and put it in the fridge, covered, within 2 hours: it keeps for up to 3 days and is very good cold in sandwiches with a little mint sauce. Reheat slices only once, until piping hot. The mint sauce keeps in a covered jar in the fridge for up to 2 days.

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