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Marion’s Ultimate Roast Lamb

For an extra-special roast, it’s hard to beat lamb. Tender, juicy and sweet, it’s a beautiful meat that elevates any family occasion. My recipe hits all the right spots and makes any day a celebration.


Marion’s Ultimate Roast Lamb

10 minutes
4 hours 40 minutes + marinating

2.5kg (5.5 lb) lamb leg 

3 red onions, halved 

6 rosemary sprigs, plus extra rosemary leaves to serve 

2 cups Chinese Shaoxing wine 



3 tbsp soy sauce 

1/3 cup miso paste 

1 tbsp honey 


Tomato miso sauce: 

1 x 400g (14 oz) tin whole peeled tomatoes 

1 tbsp miso paste 

2 tbsp oyster sauce 

1 tbsp white vinegar 

2 star anise 

1 tsp Chinese 5-spice (try my homemade Chinese 5-Spice recipe) 

  • Step 1

    Use a sharp knife to score the lamb fat. Place the onions in a roasting tray and top with the rosemary sprigs. Place the lamb on top.

  • Step 2

    Combine the marinade ingredients. Pour the marinade over the lamb and rub all over. Cover and allow to marinate in the fridge overnight or at least 6 hours. Remove the lamb from the fridge at least 2 hours before cooking so that it loses some of the chill. 

  • Step 3

    Preheat the oven to 150°C/300°F. 

  • Step 4

    Pour the Chinese Shaoxing wine into the roasting tray. Cover the lamb with baking (parchment) paper, then cover and tightly seal with foil. Roast for 3½ hours. 

  • Step 5

    In the meantime, combine the ingredients for the tomato miso sauce in a saucepan over medium-high heat. Bring to a simmer and use a wooden spoon to break up the tomatoes. Turn the heat to low and simmer for 10 minutes. Remove from heat and set aside until the lamb is ready. 

  • Step 6

    Remove the lamb from the oven and uncover. Turn the oven heat up to 200°C/390°F. 

  • Step 7

    Ladle most of the cooking juices into the tomato miso sauce, saving a couple of spoonfuls of cooking juices to baste the lamb. Place the lamb back into the oven uncovered and roast for 30 minutes or until deeply browned. 

  • Step 8

    In the meantime, place the tomato and miso sauce back on a high heat and simmer for 5 minutes to thicken slightly. If the sauce contains a lot of lamb fat, use a paper towel to soak it up or spoon it off with a ladle. Allow the lamb to rest for 20 minutes. Then carve and serve with the tomato miso sauce and a sprinkling of rosemary leaves. 

How long does it take to roast lamb?

That really does all depend on the size of your roast lamb. We’ve used a 2.5kg lamb and it takes around 4 hours to cook, plus 40 minutes marinating time. While roasting a lamb might seem quite labour intensive, it’s all worth it in the end! Low and slow is the best way to cook your roast lamb if you’re after that sweet, tender and juicy roast lamb that is sure to impress your friends and fam!

At what internal temperature is roast lamb cooked?

According to Australian Lamb, if you like your lamb rare, you’ll be aiming for around 58 degrees celsius, if you like it medium, 65 degrees celsius is your guy and for well done lamb you’re going to want to hit 70 degrees celsius.

Should lamb be covered when roasting?

To get your roast lamb super tender you will want to cover it with foil for the majority of cooking. We leave our lamb cooking covered for the first 3 and a half hours, we then remove the foil and crank up the heat for the last 30 minutes of cooking.

What is the best cooking method for lamb?

Whilst it’s hard to go past a good roast, there are so many different lamb recipes to try – with all different methods of cooking! You could whip up a lamb, cumin and leek stir fry, or some Northern Chinese lamb dumplings – or even a sichuan-style shepherd’s pie…the possibilities are endless with lamb!

Marion's Kitchen is for everyone who finds joy in flavour and happiness in every bite. Marion's Kitchen is for everyone who finds joy in flavour and happiness in every bite.

What our customers say

5.0 out of 5 stars (based on 1 review)
Very good0%

Beef short Rin

April 2, 2024

I followed this recipe and my whole family loved it

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Maxine B

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