Preparation time: 15 minutes
Cooking time: 1 hour 20 minutes

1 tbsp vegetable oil
500 g lean minced lamb
1 large onion, chopped
1 tbsp plain flour
400g can chopped tomatoes
300ml lamb, beef or chicken stock
2 fresh bay leaves
1 tsp dried thyme
1 tsp anchovy essence (optional)
2 tsp Worcestershire sauce
For the Mashed Potatoes
700 g/1 1/2 lb floury potatoes such as Maris Piper, peeled and cut into chunks
150ml semi-skimmed milk
4 spring onions
50 g unsalted butter (or olive oil based spread for a lower saturated fat option)
1 egg yolk
2 (100g) bags watercress, roughly chopped
salt and freshly ground black pepper to taste

Preheat the oven to 180°C/Fan 160°C/Gas 4. Heat the oil in a heavy based pan, add the mince and cook over a fairly high heat until evenly browned, breaking up any lumps with a wooden spoon. Add the onion and cook for 5 mins until softened but not browned, stirring occasionally.

Add the flour and cook stirring for 1 min. Then stir in the chopped tomatoes, stock, bay leaves, thyme and anchovy essence, Worcestershire sauce and a good pinch of pepper. Bring to the boil, stirring occasionally, then reduce the heat, cover and simmer for 25 mins or until the lamb is tender and sauce thickened and rich. Season to taste

Whilst the lamb cooks, cook the potatoes in boiling salted water for 15-20 mins or until tender. Drain the potatoes, then return to the pan and mash until smooth. Cook the spring onions in the milk for 3-4 minutes then tip into the mash with the butter, egg yolk and watercress and stir through with a fork, until it is nice and fluffy. Season to taste.

Spoon the lamb mixture into a 1.75 litre pie dish, discarding the bay leaves. Spoon the fluffy watercress mash on top and fluff up with a fork. Bake for 25-30 mins or until bubbling and golden brown. Serve hot with green vegetables.

Cook's tip

If you are running short on time you, after smoothing the hot mash on top of the mince you can brown it under a medium hot grill for 5 mins until crisp.