Form the patties: In a large bowl, combine the beef mince, beaten egg, breadcrumbs, onion powder, garlic powder, dried thyme, salt, and pepper. Use your hands to mix everything together gently until just combined—overworking the mixture will make the patties dense. Divide the mixture into four equal portions and shape them into oval patties, about 2cm thick. You should feel the mixture holding together without being sticky.

Sear the patties: Heat the vegetable oil in your large frying pan over a medium-high heat until it shimmers and a faint wisp of smoke rises. Carefully place the patties into the hot pan—you should hear a satisfying sizzle. Cook for 4-5 minutes on each side, until the underside is a deep, dark brown and a little crisp. The patties will release easily from the pan when they are properly seared. Transfer them to a plate and set aside. The pan should now be covered in lovely brown bits, which are pure flavour.

Sweat the onions and mushrooms: Reduce the heat to medium and add the sliced onions and mushrooms to the pan. Stir them into the pan juices, scraping up any browned bits from the bottom. Cook for 7-8 minutes, stirring occasionally, until the onions have softened and turned translucent and the mushrooms have released their liquid, which should then begin to evaporate. The kitchen will smell wonderfully earthy and sweet.

Build the gravy base: Add the grated garlic and cook for another minute until it becomes fragrant. Sprinkle the flour over the vegetables and stir constantly for 2 minutes. The flour will coat the onions and mushrooms, and the mixture will look pale and clumpy. This is the roux that will thicken your gravy.

Add the liquids: Slowly pour in the beef stock while whisking or stirring vigorously to prevent lumps. Add the Worcestershire sauce and tomato purée. Bring the gravy to a gentle simmer—you should see small bubbles breaking the surface. The gravy will look thin at first, but it will thicken as it cooks. Allow it to simmer for 5 minutes, stirring occasionally, until it has reduced slightly and coats the back of a spoon.

Finish the dish: Return the seared patties to the pan, nestling them into the gravy. Spoon some of the gravy over the tops of the patties. Reduce the heat to low, cover the pan with a lid, and let everything simmer gently for 10-15 minutes. The patties will finish cooking through, becoming tender and absorbing some of the gravy's flavour. The gravy should be rich, thick, and glossy. Taste and adjust the seasoning with a little more salt and pepper if needed.

Rest and serve: Remove the pan from the heat and let it rest for 5 minutes before serving. This allows the juices to redistribute within the patties. Garnish with fresh thyme sprigs if you like. The final dish should look deeply inviting, with glossy, dark patties swimming in a rich, mushroom-studded gravy.