Lamb shank shepherd’s pie

Heat 1 tbsp of the oil in a large casserole over a medium-high heat and brown the lamb shanks, in batches, for 2-3 minutes on each side until well coloured. Remove to a plate and set aside.

Add the remaining oil, the onion, celery, carrots, bay and a pinch of salt to the pan, cover with the lid and cook for 15 minutes until the vegetables have started to soften, stirring every now and again.

Uncover, add the garlic and cook for a minute more, then tip in the flour and cook, stirring, for a further minute. Tip in the tomatoes, stock, worcestershire sauce and rosemary. Season well, bring to a simmer, then return the lamb shanks to the pan. Cover with the lid, reduce the heat to a gentle bubble and cook for 2 hours. Remove the lid and cook for another 1-2 hours or until the lamb shanks are meltingly tender. Remove the shanks to a board, shred the meat using two forks, then stir it back into the sauce. Season to taste. You can keep the lamb mixture frozen in an airtight container for up to three months once completely cooled.

Heat the oven to 200C/fan 180C/gas 6. Tip the lamb mixture into a deep 20cm x 30cm baking dish. Cook the potatoes in a large pan of boiling salted water for 15-20 minutes until really soft. Drain well, then return to the same pan. Season, add the butter and mash until mostly smooth.

Spoon the buttery mash over the lamb mixture in the baking dish, then gently smooth out with the back of the spoon so the filling is completely covered. Drag a fork over the mash to decorate, then bake for 25-30 minutes until the mash is golden and the filling is bubbling at the edges. Serve with buttered steamed green veg.