1Heat oil in an ovenproof casserole dish. Brown the seasoned beef in batches, then set aside.
2Reduce heat, cook onions, celery and garlic until softened around 8-10 mins.
3Return beef to the pan, add thyme, bay leaves and stock. Add stout and carrots, bring to a boil, then cook in the oven until beef is tender, about 2–2½ hours at 150C.
4Adjust seasoning and cool.
5Prepare pastry base: line the pie dish with shortcrust pastry, blind bake with baking beans for 15 mins at 200C, then remove and bake a few more minutes.
6Once cooled carefully tidy up the edges with a sharp knife.
7For the mash, peal and chop your potatoes into medium chunks, boil potatoes in salted water until fork-tender, then mash or put through a potato ricer.
8Melt butter in a pan with milk and add to the mash. Then season to taste.
9Transfer filling to pastry-lined dish.
10Preheat the oven to 200C. Brush beaten egg around pastry edge, place pastry lid on top, seal, trim, crimp edges with a fork, and create steam vents.
11With any leftover pastry finish your pie with something decorative. Brush the top with remaining egg wash.
12Bake the pie for 30–35 minutes until golden and crisp.
13For the gravy, melt butter in a pan and add flour, cook for 2 minutes remembering to keep stirring then add red wine (this will thicken a lot) then whisk in stock.
14Season to taste.
15Serve the pie on top of the mash and pour over your gravy.