How To Cook Slow Roast Lamb

Slow roast lamb is a great way to enjoy a lamb shoulder. More often a roast leg of lamb is a favourite joint to cook for roast dinner. But the slow-cooked shoulder of lamb is a delicious alternative. The shoulder has layers of fat running between the meat which, when cooked slowly for a length of time, melt and baste the meat creating a succulent and flavourful dish.

Of course, if you wish to slow roast lamb leg do give that a try as well. Just be sure to add moisture during the cooking process with a stock, or wine, or even just water. Remember, it’s the layers of fat in a lamb shoulder that keep it moist whilst cooking at a low temperature for a longer period of time. This makes the meat so succulent.

How to cook lamb shoulder in the oven

Cooking a lamb shoulder is incredibly easy. You simply need a good-sized joint of lamb shoulder, a marinade of your choosing, and the patience to let the lamb cook on a low temperature in the oven for around 6 hours. This is where the term ‘low and slow’ comes from. Low cooking temperature and a slow cooking time allows for the most succulent meat.

Lamb shoulder cooking time

Like all meats, the cooking time for the lamb shoulder does depend on the size of the joint and the temperature/efficiency of the oven.

In our experience, you can slow cook a lamb shoulder in 4 hours at 130C-140C if it is around the 1kg-1.5kg. So that means the ideal temperature for slow roast lamb temperature in celsius is at the 130 degree celsius mark in a fan oven. This is about 300 degree Fahrenheit and Gas Mark 2.

But for the most succulent, fall-apart lamb texture we recommend around 6 hours for a 2kg joint at 130C.

Of course, it is worth experimenting with your oven as temperatures can vary from oven to oven. We recommend investing in an oven thermometer. This stainless steel thermometer looks great. 

The best way to know when the slow roast lamb is ready is to take it out of the oven and use a fork to push back on the meat near the bone, it should start to come away easily leaving the bone clean. The best slow roast lamb shoulder is when the shoulder bone can be pulled out with ease leaving just the meat behind.

Roast lamb marinade options

For our slow roast lamb recipe below we have recommended our popular marinade option of garlic, chilli, and salt. This is a personal preference, of course. Do experiment with some of your favourite flavourings. 

We recommend picking your favourite spices to create your own unique marinade for the lamb shoulder.

Popular spices for lamb include:

• ground cumin
• ground coriander
• thyme
• rosemary
• paprika
• cumin seeds
• whole garlic (pierce the lamb with a sharp knife and pop slices of garlic cloves straight in)
• black pepper
• fennel seeds.

We recommend you use the best quality salt you can such as a good pinch of Maldon Sea Salt. 

You can use a garlic puree to create a wet texture to allow the marinade to stick and eventually create a chewy bark. The bark is where the slow-cooked meat creates a firmer outside that is chewy in texture. This contrasts beautifully with the tender and soft meat underneath.

When making a marinade you can either create a dry rub which is a combination of dry spices patted into the meat. Or you create a wet marinade using a liquid such as oil to bind the spices together.

What is slow-cooked lamb meat bark?

Meat bark is when the skin of roasted meat becomes slightly hardened and chewy. It adds a nice textural contrast to the soft and succulent meat underneath. It also adds an interesting flavour profile which has depth to it.

If you would prefer not to have the chewy skin, aka. bark, you can cover the roasting tin containing the lamb loosely with foil for the slow roasting process.

How much lamb shoulder do I need to slow roast?

A 2KG lamb shoulder should comfortably feed between 4-6 people. Adjust the cooking time according to the size of the meat.

Should I cover lamb with foil when roasting?

This depends on whether you want the chewy bark texture on the outside. If you want the entire joint of meat to be soft and tender then cover with foil. Otherwise, leave it uncovered for the cooking time and just cover with foil when you remove it at the end to rest on the side.

Slow Roast Lamb (serves 4-8)

Ingredients

• 1.5kg+ Shoulder of Lamb
• 2 tbsp Garlic Puree (optional)
• 1 tsp Dried Chilli Flakes (optional)
• Large pinch of Maldon Sea Salt

Method

1. Take the lamb shoulder out of the fridge at least an hour before cooking. Preheat the oven to 180C (fan) / 400F / Gas Mark 6.
2. In a bowl mix together the garlic puree, chilli flakes, and sea salt, or a marinade of your design or choosing (see above for ideas).
3. Put the lamb onto a large baking tray and spread the marinade all over the meat. Roast the lamb in the preheated oven for 30 minutes to start.
4. After 30 minutes lower the temperature of the oven to 130C (fan) / 300F / Gas Mark 2. Slow roast the lamb for a minimum of 4 hours, 6 is the best length of time for a 1.5-2kg joint. Baste the lamb shoulder approximately every hour with the juices settling at the bottom of the pan.
5. Remove the lamb joint from the oven, cover with foil and allow it to rest for at least 30 minutes.
6. Carve the joint using a sharp knife to loosen the thick skin (aka the bark) particularly around the bone. The meat will fall easily from the bone.

Serve immediately with roast potatoes and roast dinner sides, or allow to cool to use in other meals such as shepherd’s pie, curry, or a leftovers sandwich.  

You might also like these other lamb recipes:

• Roast Leg of Lamb
• Leftover Lamb Massaman Curry
• Leftover Lamb Satay Disco Fries
• Persian-Style Lamb Pie with Mint and Pomegranate

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