Slow-cooked lamb shoulder with boulangère potatoes

Revamp your Sunday roast with the ultimate lamb and potato combo, traybake style.

A picture doesn’t do this dish justice. Lamb is by far my favourite meat for a roast dinner – and this is my favourite way to cook it.

A large lamb shoulder, coated in a punchy garlic and paprika marinade, left to cook low and slow until the skin is crisp and gnarly and the meat literally pulls away from the bone.

Now for the best bit: the sliced potatoes act as a trivet for the lamb and catch all those gorgeous juices as they trickle down. Think duck fat roasties, but better!

While the lamb rests, set aside a good 30 minutes to crisp up the potatoes – the result is truly spectacular. 

How To Make Slow-Cooked Lamb Shoulder With Boulangère Potatoes

• Chef Catling’s recipe notes
• Recipe: Slow-cooked lamb shoulder with boulangère potatoes
• Frequently asked questions

Tips & Notes To Know

• Buy bone-in lamb shoulder: It has more flavour than boneless cuts and is a lot more juicier, too. It’s ideal for slow cooking as the collagen breaks down and bastes the meat naturally.
• Embrace the lighter touch: Boulangère potatoes are a healthier alternative to the richer gratins you might know and love, like dauphinoise potatoes. There’s no cream here, just lamb stock, onions and a few herbs. The result is beautiful tender potatoes with a golden, crispy top.
• Choose waxy potatoes: Floury spuds like Maris Piper and King Edward break down too much. Charlotte or Desiree are more robust and hold their shape while roasting.
• Slice the potatoes evenly and thinly: Now’s the time to put your mandolin to good use. If you don’t have one, aim for a 2-3mm thickness for each potato slice.
• Let the lamb sit in its juices for 10 minutes after cooking: The fat will naturally rise to the top and separate from the jus. You can either use a spoon to gently skim off the top oily layer or, better still, use your gravy separator jug to leave the fat behind.

Slow-cooked lamb shoulder with boulangère potatoes

Serves: 4 Prep time: 10 Cook time: 4+ hours 4+ hours

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Ingredients

1 tbsp olive oil
1/2 tbsp smoked paprika
1 tsp dried rosemary
4 smoked garlic cloves, 2 crushed, 2 sliced
2kg lamb shoulder, bone in
4 large waxy potatoes, peeled and cut into 2cm slices
2 brown onions, peeled and thickly sliced
2 dried bay leaves
Small handful of fresh thyme
500ml lamb stock
1 tbsp plain flour
1 tsp redcurrant jelly
1 tsp cornflour, optional

Instructions

Step 1
Preheat the oven to 220C. In a pestle and mortar, mix the olive oil, smoked paprika, rosemary and crushed garlic cloves together and pound to a paste. Trim the fat from the lamb, then spread the paste all over the shoulder until thoroughly coated.

Step 2
Place the lamb shoulder in a deep roasting tin, skin-side up. Using a sharp knife, make several incisions all over the meat and insert the garlic slices into the holes. Roast the lamb shoulder for 40 minutes.

Step 3
Meanwhile, add the potatoes to a pan of salted boiling water and cook for 4 minutes. Drain well and leave to steam dry on a wire rack for 15 minutes.

Step 4
Remove the lamb from the tin and place the potatoes and onions in the bottom. Add the bay leaves and thyme sprigs and pour over the lamb stock. Place the lamb shoulder back on top, skin-side up, and cover the tin tightly with tinfoil.

Step 5
Turn the oven down to 150C. Roast the joint for 4 hours, basting occasionally, until the lamb is tender and the meat is starting to pull away from the bone.

Step 6
Once cooked, transfer the lamb to a chopping board and cover with tin foil. Leave to rest while you make the gravy.

Step 7
Pour the lamb fat from the tin into a fat separator and put the boulangère potatoes back into the oven. Increase the heat to 220C and cook for 30 minutes, turning once, until crisp and golden.

Step 8
Once the liquid fat has floated to the top of the jug (this will take about 10 minutes), pour the juices into another measuring jug until only the fat remains in the separator. Top up the lamb cooking liquid with boiling hot water to make 350ml. Set aside.

Step 9
Heat one tablespoon of the lamb fat into a small saucepan over a medium heat and whisk in the plain flour. Cook out for 2 minutes, stirring regularly, so a smooth paste forms.

Step 10
Stir in the lamb cooking liquor with the redcurrant jelly and bring to the boil. Turn down to a simmer and leave to blip away gently for 10 minutes. If you like a thick gravy, mix some cornflour with a splash of cold water and whisk into the gravy until smooth and glossy.

Step 11
Shred the slow-cooked lamb shoulder and serve alongside the boulangère potatoes with the lamb gravy on the side.

Frequently Asked Questions

What Are Boulangère Potatoes?

Translated as baker’s potatoes, boulangère potatoes are a lighter and lower calorie alternative to dauphinoise potatoes that tastes every bit as luxurious. Thinly sliced potatoes are layered with onions and cooked slowly in a rich stock until it starts bubbling at the edges.

My version is pimped up with smoked garlic, thyme and redcurrant jelly, which adds an extra depth of flavour to this French classic.

How Do You Thicken The Sauce?

Mix 1 tablespoon each of cornflour and water until well combined. Gradually stir the cornflour slurry into the lamb gravy until it reaches the desired consistency.

Should I Use Fresh Or Dried Herbs?

Dried herbs are an inexpensive staple in my store cupboard and tend to have a deeper flavour than fresh. They benefit from some cooking to rehydrate the leaves, though if you add them too early to a dish or boil them to death, they will turn black and potentially ruin the final product.

Fresh, leafy herbs like basil, parsley and coriander are best added towards the end of cooking (or preferably after) to preserve their fragrance and vibrancy, while woody herbs like rosemary and thyme can be used in place of dried.

A good ratio is 1:3, so instead of using 1 teaspoon of dried rosemary, use 1 tablespoon of fresh.