Preheat the oven to 190oC / 375oF / 170oC Fan / Gas Mark 5

Heat the olive oil in a large frying pan / skillet over a medium heat and add the chopped onion. Fry for 2 - 3 minutes, stirring until the onions have started to soften slightly.

Add the garlic and continue to fry for 1 minute before adding the chopped leeks.

Add a splash of water if it looks like the onions or garlic are going to stick to the pan (this really depends on how non-stick your pan is!).

Stir for a further 2 - 3 minutes until the leeks start to soften and they begin smell wonderful. 

Add the sliced mushrooms and stir for 3 - 4 minutes until they have softened slightly. Again, add a splash of water if needed. 

Add the stock, stir, turn up the heat and bring to the boil. Once the mixture has started to boil, reduce the heat and simmer for 10 minutes before adding the chicken pieces.

Stir the mixture, then leave to simmer for a further 15 minutes, stirring occasionally.

By this time the stock should have reduced by about ⅓. Turn off the heat, season with salt and pepper and stir in the cream cheese.

Spoon the filling into an oven proof dish. 

Cut each sheet of filo / phyllo pastry into 2. Spray each piece with 4 or 5 pumps of spray oil.

Scrunch up the pastry and lay it on top of the pie filling, oil side facing up. 

Place in the preheated oven for 15 - 20 minutes until the filo pastry has turned golden brown.

Remove from the heat and serve with garden peas.