Place all the ingredients in a large stock pot and bring to a boil.

Reduce the heat and simmer for an hour until the chicken is cooked all the way through, if your chicken is larger it might take longer to cook so be mindful of the time.

Remove the chicken and leave to cool before shredding.

Reduce the stock until it is half, should take another 20-30 mins. Turn off the heat and strain the stock into a large glass jar. Keep the veggies for the filling.

In a food processor pulse the flour and cold butter until fine breadcrumbs. Add the water tablespoon at a time and keep pulsing until a dough forms. Divide the dough into two halves. Wrap in cling file and leave to chill for 30 mins in the fridge.

Alternatively you can make this with your hands by rubbing the flour and butter together until you achieve the breadcrumb consistency. Add the water as suggested and form a ball. Don’t knead it like you would with bread.

Roll out one half of the pastry dough to 1/2 inch thickness.

Using the rolling pin transfer the dough into a 11x3 inch rectangle baking tray, ensuring the pastry is coming up on the sides and cut off the excess pastry dough that hangs over the tray.

Poke holes into the dough with a fork (docking) and place a large sheet of baking paper on top of the pastry dough, fill with lentils/legumes/baking beans (this is blind baking).

Bake in a preheated oven at 180℃ for 20 mins until the pastry has colored lightly and is dry to the touch.

Remove the dried legumes/lentils/baking beans and the baking paper, bake again for 5 mins.

In a sauté pan on medium heat add the butter, onions, leeks, carrots and celery. Sweat on low heat until it has softened.

Add the mustard, garlic, peas and corn, stirring well.

Add the corn flour and stir again.

Add the chicken, herbs, and vinegar. Stir everything around, being gentle.

At this stage you can mash up the leftover veg from the stock or add it in directly as it will be very mushy they won’t stay chunky in the filling. I like mashing it up a little. This is an optional step.

Add the stock and let the mixture bubble a little, reduce the heat and add the milk, cream and cheese. Stir constantly until everything is combined.

Season well.

Roll out the 2nd half of the pastry dough to 1/4 inch thickness.

Pour the filling into the blind baked pastry.

Cover with the rolled out pastry dough. And seal the edges with your fingers by pressing into the blin baked pastry.

Dock with a fork on the top and brush with cream.

Bake at 180℃ for 35-40 mins until the top is golden brown.

Let it cool for 20 mins before serving.