Preheat your oven to 200 degrees Celsius.
Heat a large pan on a medium heat and spray well with 1 kcal spray.
Wash the leek and slice it into thin pieces.
Add the leek, garlic and baby mushrooms to the pan and cook for 2-3 minutes until the leek starts to soften.
Add in the chicken and fry for 2-3 minutes until starting to colour.
Pour in the chicken stock and allow it to come to a simmer.
Meanwhile, in a cup, mix the cornflour with a tablespoon of water to make a paste.
Add the paste and the extra light cream cheese to the pan and stir well.
Bring to a simmer and stir until the sauce starts to thicken.
Taste and season as required with the mixed herbs, salt and pepper.
Remove from the heat and stir in the spinach.
Pour the mixture into your pie dish and leave aside to cool slightly.
Scrunch up the filo pastry sheets and cover the pie.
Spray the whole pie well with 1 kcal spray.
Bake your pie in the oven for 20 minutes until the pastry is golden brown and crispy.