Preheat your oven to 220 degrees & place the chicken fillets into a loaf sized tin & add the marinade, coat all surface of the chicken & place into the oven, uncovered for 20 minutes (please see notes).

Cook the onions on a medium heat in the butter (or your preferred substitute) for 5 minutes then turn down the heat & add the mushrooms, cook for a further 5 minutes. Now add the stock & cream & heat till just simmering. Check the chicken & if ready (keeping the oven on & turning it down to 180 degrees), cut into bite sized pieces, then mix well with all the juices & add to the pan, bring to a slow boil. Add one heaped teaspoon of cornflour mixed with a little water (start with just a little until the desired thickness is required for your pie filling), remove from the heat & add the spinach. Mix well & place into a 22cm x 22cm casserole dish now tear up the filo pastry roughly & place on top. Bake for 20 minutes or until the pastry is golden brown

NOTES

Please make sure you cook the chicken in a small dish which allows the chicken to cook in the marinade ie in a single layer without any large gaps around the edges or the marinade will disperse & burn

This is considered a light pie, you could substitute the butter for water to cook the onions & swap the single cream with creme fraiche or quark too to make it even lighter! I have made this with both shortcrust & puff pastry too & all were amazing!

Keep an eye on this dish when browning in the oven especially if using filo pastry as it cooks very quickly & can burn in an instant