Sepherd's Pie

* INGREDIENTS

- 1 tbsp rapeseed oil
- 1 onion, chopped
- 2 carrots, diced
- 250g lamb mince
- 1 tbsp plain flour
- 350ml vegetable stock
- small can chopped tomatoes
- 1 tbsp tomato puree
- 400g can green lentils, drained
- 1 tsp Worcestershire sauce
- 650g potatoes, roughly chopped
- 250g sweet potatoes, roughly chopped
- 2 tbsp half-fat creme fraiche
- 1 tbsp semi-skimmed milk


* METHOD

1. Heat the oil in a large pan. Tip in the onion and thyme springs and fry for 2-3 minutes. Add the carrots and cook for 5-8 minutes more, stirring occasionally. Stir in the mince, breaking it up with a wooden spoon, and fry until brown.
2. Simmer. Add the flour, stir well, then cook for another 1-2 minutes. Pour in the stock and stir until thickened. Stir in the tomatoes, tomato puree, lentils and  Worcestershire sauce. Reduce the heat and simmer, covered, 45 minutes, stirring occasionally.
3. Make the topping. Meanwhile, cook the potatoes and sweet potatoes in a large pan of boiling water. Bring back to the boil, then simmer for 12-15 minutes, or until tender. Drain well,  then tip back into the pan. Mash until smooth. Beat in the creme fraiche and milk with a wooden spoon, until light and fluffy.
4. Bake. Turn oven to fan 180C/conventional 200C/gas 6. Spoon the meat into a 1.5 Litre pie dish and remove the thyme springs. Top with the mash and smooth over with a knife. Bake for about 20-25 minutes, or until piping hot and bubbling and the top is crispy and golden (you could grill it for the last 5 minutes to get it extra-crispy on top if you like).