Cut the celery stalk to fit your cooking pot or pressure cooker. Put the parsley and thyme into the groove of the celery, and tie it securely with some clean cooking string.

Fry the bacon in oil until starting to become golden and crispy, then add the mushrooms and continue to cook until they have released excess liquid.

Season and brown the beef in small batches to get a good color on it without crowding your pan.

Saute the carrots until they are just starting to catch a little color, then add the onion and continue to saute until softened.

Add the crushed garlic, and cook off for a minute before adding the ale and scraping up anything from the bottom of your pan.

Add the beef back into the pan together with the celery and herbs, bay leaves, mustard, worcestershire sauce, black treacle, beef stock, and pepper.

If pressure cooking, stir, seal the lid, and cook on high pressure for 35 minutes, then natural release.

If cooking in the oven, add 300ml water, bring to a simmer, and transfer to the oven with a lid on, cooking for approximately 2 to 2.5 hours.

Add the bacon and mushrooms back into the mix and simmer for 15 minutes to reduce the sauce. Mix cornflour with cold water and stir in to thicken the sauce.

Divide the mixture between pie dishes, cool, and place into the fridge to chill.

Top your pies by moistening the edges of the dishes and placing a disc of pastry on top. Pinch the edges, brush with eggwash, and poke holes for steam.

Pre-heat the oven and place the pies in the middle to cook for around 30-35 minutes until the pastry is golden.