Dice the onions, celery and carrot. Chop the zucchini and shred the chicken. Take the pastry out to defrost.
If you are making these in the oven, preheat to 200 degrees celsius.
Add the olive oil to a fry pan. Add the onion, carrot, celery and fry until the onion is soft.
Add the zucchini and cook for 2-3 minutes.
Add the frozen peas and thyme and mix well, cooking for 1 minute.
Add in the chicken stock and bring to the boil.
Mix the cornflour into the cream and add to the pan, cooking until thick and creamy.
Add the chicken and heat through.
Cut circles from the pastry.
Add the shortcrust to the base of your pie maker.
Fill with the filling.
Top with puff pastry.
Cook until golden and warmed through.
Put the shortcrust pastry into the bottom of a greased pie pan.
add the filling and top with puff pastry, pressing down the edges.
Brush with milk and bake for 20 minutes at 200 degrees celsius or until golden and cooked through.
Cooked chicken: if you don't have any and would prefer to cook the chicken as you make these, I recommend using 1 chicken breast. Dice it and pop it into the pan as soon as the onion has softened. Leave it in the pan for all of the cooking.