In a large pan, heat the olive oil over a medium heat. Add the onions and sauté for three minutes. Add the remainder of the vegetables and cook for 10 minutes, stirring occasionally.
While this is cooking, remove the skin from the chicken and discard. Take all the chicken off the carcass and shred with your fingers.
When the vegetables are cooked through, add the flour, bay leaves and chicken stock cube. Add the water and stir through well, this should create a gravy. Add the chicken to the mixture and season to taste. Leave to simmer for 10 minutes.
Pre-heat your pie maker or your oven. Cut your pastry into circles for the base and for the top. If you're using a pie maker, they usually come with a tool for this but if you're using a muffin tray, you may have to do a little guess work. Line each pie tray with pastry and spoon in the chicken mixture into the pastry. Top with a circle of pastry and close your pie maker. Cook for approximately six minutes or until golden brown. As a tip, if you have leftover bits of pastry, combine them in a ball and roll it out with a rolling pin before cutting more circles.