Turn your oven to 200°C/Gas Mark 5.
Bring a medium sized pan of water to the boil, add the sliced potatoes and cook for 5 minutes, drain and leave to cool. In a large pan add 1 tbsp. of the olive oil and cook the onion, carrot and leek until they start to colour over a medium heat.
Now add the lamb and continue cooking for a couple more minutes before stirring in the flour. Deglaze with the Worcestershire sauce then pour in the lamb stock and bring to a steady simmer, add the rosemary, leave it ticking away and season to taste.
Now heat up the last of the olive oil in a large frying pan and cook the sliced blanched potatoes until they start to turn golden.
Pour the lamb into a medium sized oven dish, top with the potatoes, place in the oven and cook for 10-15 minutes.
This is perfect with pickled red cabbage or any vegetable of your choice.
400g baby potatoes (such as Charlotte), sliced into 3
400g leftover roast lamb, cut into chunks
1 onion, roughly chopped
2 carrots, sliced thinly
1 leek, thinly sliced
2 rosemary sprigs
2tbsp olive oil
1tbsp Worcestershire sauce
1tsp plain flour
400ml lamb stock