This comforting slow-cooker steak pie features tender beef chunks simmered in a thick, peppery gravy with fresh celery and carrots and a flaky puff pastry top.
Mix the flour and mustard powder in a medium bowl and toss with the stewing steak. Heat the oil to brown the beef. Do this in two batches to ensure a good sear and colour on the beef and avoid overcrowding the pan. *see notes
Once you have browned the beef, add the onions and minced garlic with a splash of the stock to deglaze the bottom of the pan and scrape up any brown bits. Cook for about 5 minutes until the onions are soft and tender. Spoon the beef and onions into the bowl of your slow cooker.
Stir in the carrots, celery, tomato puree, Worcestershire sauce, the remaining stock, and the thyme leaves. Cook in the slow cooker on low for 8 hours and high for 5.
Once the beef has slowly cooked for the allotted time, test it and ensure it's tender. Spoon the beef pie filling into a pie dish and let cool for a few hours before adding the puff pastry lid.
Adding the puff pastry lid
Pre heat your oven to 190ºC (fan) 200ºC conventional. Once it has cooled, place the steak filling in a pie dish and place the pastry on top. Using a sharp knife trim the excess pastry from around the edges of the dish. Use a fork to seal the edges to the rim.
Brush the top of the pastry with beaten egg and sprinkle with some sea salt. Bake until the filling is hot and the pastry is golden and puffed up about 20-25 minutes.
Notes
If you have a sear-and-cook slow cooker, heat the oil right in the bowl of the slow cooker over medium heat. If not, use a heavy-bottomed pan and heat the oil over medium heat.
To cool the steak pie filling quickly: spoon the stew into a shallow container with a large surface area and place it in the freezer for about 15 minutes, then use a spoon to stir it around and place it back in the freezer for another 15 minutes. Continue to do this until the filling has cooled.
The quantity of garlic will depend on personal preference and the size of your garlic cloves.