Add the chicken pieces to a plastic bag and spoon in a tablespoon of flour, seasoning well with salt and pepper. Shake to coat the chicken.

In a non stick fry pan, add a dash of olive oil and working in batches, fry the chicken until browned. Reserve in to the slow cooker.

Adding a dash more olive oil to the same fry pan, sauté the onion, garlic, bacon, celery and leek until slightly softened. Add the mushrooms and continue to cook for another couple of minutes.

Now sprinkle over the dried thyme and one tablespoon of flour and continue to cook. Pour in the chicken stock and bring to the boil. Stir through the mustard and cream.

Pour this mixture in to the slow cooker, combining with the chicken. Cook on high for 4 hours or until the chicken is extremely tender. (NB: Make sure you mix every now and then to avoid the mixture catching on the bottom. Add a dash more water if it needs it).

Taste the mixture for seasoning, adding more salt and pepper if needed. Let it cool slightly.

Preheat the oven to 220℃.

In a round pie dish, grease with a little butter and add one of the pastry sheets, pressing it down slightly so that it fits in to the dish, hanging over the edges a little bit.

Pour in the chicken mixture and add the second piece of puff pastry, placing it on a diagonal so that the two sheets of pastry create a star shape.

Prick the top of the pie using a fork and using a pastry brush – give the top a good wash with the beaten egg (this helps the pastry become lovely and shiny when cooked).

Place in a very hot oven (220℃) for the first 10 minutes and then back the heat off to 180℃ and cook for another 20-30 minutes or until nicely golden.

Serve with the mashed potato and steamed veggies.