Lamb shank shepherd's pie with herby mash

Ingredients

• 2 lamb shanks, approx. 350–400g each
• 2 tbsp vegetable oil
• 1 bottle of red wine
• 1 onion, halved
• 2 celery sticks, roughly chopped
• 2 carrots, roughly chopped
• 2 garlic cloves, bashed
• 2 bay leaves
• 2 thyme sprigs
• 400 ml lamb stock
• 100 g tomato purée
• 1 tbsp Worcestershire sauce
• 2 onions
• 2 celery sticks
• 3 carrots
• 1 courgette
• 1 leek, white part only
• 50 g unsalted butter
• 1 kg maris piper potatoes, peeled and cut into chunks
• 100 g unsalted butter
• 50 g dijon mustard
• 2 medium egg yolks
• 1 x 20g pack tarragon, leaves chopped
• 1/2 x 30g pack flat-leaf parsley, leaves chopped, plus extra to serve (optional)

Instructions

1. 1

   Preheat the oven to 190°C, fan 170°C, gas 5. Season the lamb shanks well. Heat the oil in a large frying pan over a high heat and sear the shanks until well browned all over (about 5 minutes). Transfer to a deep roasting tin. Deglaze the pan with a splash of the red wine, scraping up any caramelised bits, and pour over the shanks. Add the onion, celery, carrots, garlic and herbs to the dish, then pour over the remaining wine and lamb stock (the shanks should be submerged, so add extra water if needed). Cover tightly with foil and braise in the oven for about 3 hours, or until the lamb is falling off the bone.

2. 2

   Remove the shanks from the cooking liquor and set aside to cool slightly. Strain the liquor through a sieve into a large pan, discarding the braising vegetables. Bring to the boil, then reduce over a medium heat until you have about 400ml of liquid that coats the back of a spoon. Meanwhile, shred the lamb from the bone, discarding any fat or sinew. Stir the tomato purée and Worcestershire sauce into the reduced liquor, return to the boil, then remove from the heat.

3. 3

   For the diced vegetables, cut all the vegetables into 1½cm dice. Melt the butter in a large pan over a medium heat. Add the onion, celery, carrots and courgette, then sweat gently for about 10 minutes until the carrot is just tender but still has a little bite. Stir in the leek and cook for 2 minutes, then remove from the heat.

4. 4

   For the mash, cook the potatoes in a large pan of salted boiling water for 15-20 minutes, until tender. Drain well, then mash. Beat in the butter, mustard and egg yolks, then stir through the herbs and season.

5. 5

   Preheat the oven again to 190°C, fan 170°C, gas 5. Fold the lamb and vegetables into the sauce until combined. Transfer to a deep baking dish (approx. 20cm x 25cm) and spoon the mash over the top. Spread to the edges and rough up with the back of a fork. Bake for 25-30 minutes until golden. Stand for 10-15 minutes, then top with extra parsley, if liked.