Cooking a shoulder of lamb over sliced potatoes allows the meat juices to run into the potatoes as they cook, resulting in a wonderful, savoury alchemy. The lamb ends up fork-tender and the potatoes take on a gorgeous richness. Mushrooms give the dish a third, earthy dimension. This is a real winter warmer.
Prep: 20 mins
Total Time: 3-4 hours
- 1 shoulder of lamb, hogget or mutton, on the bone (about 2kg)
- A little olive oil
- 1.25kg large white potatoes
- 1 large onion, finely sliced
- 2–3 large garlic cloves, sliced
- 2 long stems of rosemary, leaves only, chopped (optional)
- 300g Shitake mushrooms, thickly sliced
- Sea salt and freshly ground black pepper
- Preheat the oven to 220C. Put the lamb in a large roasting tin. Trickle with a little olive oil and season well with salt and pepper. Roast for 25–30 minutes until golden. Meanwhile, peel the potatoes and cut into slices no thicker than a $1 coin.
- Remove the lamb from the roasting tin and set aside on a plate. Turn the oven down to 150C. Splash about half a glass of hot water into the hot roasting tin and use a spatula to loosen any bits stuck to the bottom. Spread a layer of potato slices over the base of the roasting tin, on the meat juices. Don’t bother to make it too neat.
- Scatter over a little of the onion, garlic and rosemary, if using, then add a layer of mushrooms. Season with salt and pepper. Repeat this process to use up all the ingredients – aim for two or three layers, finishing with potatoes on the top.
- Place the lamb on top of the potatoes. Cover with foil, sealing the edges well. Return to the oven and cook undisturbed for 3 hours.
- Transfer the lamb to a warm plate to rest. The veg underneath should be completely tender – cooked in the juices and fat from the roasting lamb and transformed to a rich, meaty-flavoured potato and mushroom gratin. To top it off with a lovely crisp golden crust, preheat the grill to high. Put the tin of veg under the grill for 5–6 minutes until golden brown and crisp on top.
- Serve the lamb thickly sliced with the potatoes and some simply steamed greens, such as leeks and kale. Or a sharply dressed leafy salad will go well with, or after, the meat and potatoes.