Cottage pie with celeriac mash crust

SERVES 6 Per serving: Carbohydrates, 18g; protein, 40g; fat, 55g; fibre, 9.8g; calories, 750

3tbsp olive oil or beef dripping

125g butter

1 leek or 2 onions, finely sliced

600g mixed root vegetables, such as carrot, turnip, swede, celeriac, cut into 1cm cubes

Few sprigs fresh thyme

2 bay leaves

800g beef mince

3 tbsp Worcestershire sauce

2 tbsp tomato puree

600ml hot beef stock or water

2 tsp salt

Freshly ground black pepper

1kg celeriac, peeled and roughly chopped

125ml double cream

HEAT the oven to 220c/gas mark 7. Heat 2tbsp of the oil with 50g of butter in a saucepan and fry the leek for about 5 minutes over a medium heat. Add the diced root vegetables and herbs and fry for 10 minutes, stirring frequently. Remove the vegetables and place in an ovenproof dish. Add the remaining oil to the pan and fry the mince over a high heat until brown. Tip the vegetables back into the pan and add the Worcestershire sauce, tomato puree and stock. When the liquid starts to bubble, turn the heat to low and push the vegetables under the surface and leave them for 30 minutes. Meanwhile, cook the celeriac in salted water until tender. Drain and mash with 50g of butter and the cream. Taste and season as necessary. Spoon the meat and vegetables into the ovenproof dish and top with dollops of the mash. Use a fork to spread the mash out evenly. Dot the remaining butter on top and bake for 20 minutes or until lightly browned. Serve with green vegetables.