Vegetarian pie

Ingredients
2 tbsp olive oil
2 onions
2 celery sticks,
3 carrots,
400g can chopped tomatoes
425ml/ ¾ pint vegetable stock
2 tbsp tomato puree
100g/4oz red lentils
3 tbsp pesto (preferably fresh)

FOR THE TOPPING
1kg/2 lb 4oz floury potatoes
1 bunch spring onions
125ml/ 4fl oz milk
Freshly grated nutmeg
25g/1oz butter
100g/4oz grated cheddar or gruyere

Method
1. Slice the onions, celery and carrots using the thin slicing plate. Heat the oil in a large pan, add the onions and fry for 10 minutes, until softened. Add the celery and carrots and fry for 5 minutes. Stir in the tomatoes, stock, tomato puree and lentils. Bring to the boil, then cover and simmer for 20 minutes until the lentils are tender. Season well, stir in the pesto and tip into a 1.7 litre/3 pint ovenproof dish.
2. Meanwhile, peel the potatoes and cut into even sized pieces. Cook in salted water until tender. Chop the spring onions and put into a small pan with milk and a good sprinkling of nutmeg. Bring to the boil, then simmer for 5 minutes and remove from the heat.
3. Drain the potatoes and place into the mixer bowl fitted with the k beater. Mix on speed 3-4 until fairly smooth then add the milk, spring onions, butter, two thirds of the cheese and plenty of seasoning. Spoon over the filling, sealing it in.
4. Preheat the oven to 200°C/gas 6/fan oven 180°C. Sprinkle over the remaining cheese and bake for 30 minutes, until the top is crisp and golden.