Leek, mushroom and blue cheese pie

This is one of those dishes that you throw together from what's in the fridge - a few leeks, half a packet of filo pastry, some blue cheese - and it turns out to be unexpectedly delicious.

Like my previous recipe, leeks are the star of the show. I think these two dishes show what a versatile vegetable leeks are - from a light and elegant salad to rich and hearty pie.

Filo pastry is much lower in fat than other types of  pastry, so you can enjoy this pie, perhaps with some more vegetables on the side, and feel relatively virtuous at the same time.

Ingredients

Serves 4

2 knobs of butter
500g leeks, thickly sliced
200g button or field mushrooms, washed and cut into halves or quarters
50g walnut halves or pieces (optional)
1 tsp dried thyme or several sprigs fresh thyme, leaves picked
100g blue cheese, such as Stilton or Cornish Blue
200g filo pastry

Method

Heat a knob of butter in a large frying pan and add the leeks, the thyme and some black pepper. Cover and cook for 5 to 10 minutes, stirring occasionally.

Cook the mushrooms in another frying pan with the other knob of butter. Season with salt and pepper.

Grease a cake tin and line with three layers of filo pastry. It's usually recommended to brush each layer with melted butter or oil, though I don't always bother.

Put half the cooked leeks into the pastry, then crumble half the cheese on top and add half the mushrooms. Repeat with each layer, then fold over the overhanging pastry sheets. Add some more pastry sheets if it's needed to form a lid.

Bake at gas mark 6/ 180C/ 360F for about half an hour. Cover towards the end of cooking time if the pastry seems to be getting too browned.