8 oz (225 g) pasta shells
3 tbsp (1 1/2 oz) 40 g margarine
2 leeks, trimmed and sliced
2 1/3 cup (175 g) mushrooms, sliced
1/4 cup (1 oz) 30 g plain flour (All purpose)
1 1/4 cup (1/2 pint) 300 ml chicken stock
2/3 cup (150 ml) 1/4 pint milk
salt and freshly ground black pepper
4 oz (110 g) mature Cheddar cheese
1. Preheat the oven to 375°F (190°C) Gas Mk 5.
2. Cook the pasta as directed on the packet.
3. Drain and rinse well under cold water.
4. Melt the margarine in a saucepan, add the leeks and fry for 10 minutes until tender.
5. Stir in the mushrooms and cook for a further few minutes.
6. Gradually stir in the flour and cook for 1 minute, then slowly pour in the stock and milk.
7. Bring to the boil, and cook, stirring until the mixture has thickened.
8. Remove from the heat, stir in the cooked pasta and add salt and pepper to taste.
9. Pile the mixture into a 2 pint (1.2 L) ovenproof dish and sprinkle the Cheddar cheese over the top.
10. Cook in the oven for 15-20 minutes until the cheese has melted and the pasta is warmed through.