Stir fry the chicken in a little oil, in a large frying pan or saute pan, until cooked through. Add your chopped and cleaned mushrooms and keep stir frying until the mushrooms have softened. Drain any excess mushroom juice from the pan and add your tin of condensed soup. Warm the mixture and then transfer to an ovenproof dish or separate small dishes (as required).
Roll out your puff pastry, onto a lightly floured board and cut the pastry to the shape/shapes of your dish/dishes that you want to cover.
Cover the chicken mixture with the puff pastry top and brush with a little milk (if required). Cook in a preheated oven, following the puff pastry cooking instructions.
Once cooked you may have to leave the pie/pies to cool for a few minutes before serving. Serve with a selection of vegetables.