Sear the beef: Pat the beef dry with kitchen paper, then season all over with salt and pepper. Heat the oil in a large, heavy-based casserole dish over medium-high heat until it shimmers. Add the beef and sear for 4-5 minutes on each side until a deep, dark brown crust forms. You should hear a steady sizzle — if it's silent, the pan isn't hot enough. The smell at this stage is rich and meaty, promising good things to come.

Sweat the aromatics: Remove the beef to a plate. Reduce the heat to medium and add the chopped onions. Stir them around, scraping up the browned bits from the bottom of the pan. Cook for 5-6 minutes until the onions turn translucent and soft, with a sweet, savoury aroma. Add the garlic and tomato purée, stirring for another minute until the purée darkens to a rusty red colour.

Build the braising liquid: Pour in the beef stock and Worcestershire sauce, stirring well. Drop in the bay leaves and thyme sprigs. Bring the liquid to a gentle simmer — you'll see small bubbles breaking the surface, but no vigorous boiling. Return the beef to the pot, nestling it into the liquid. The liquid should come about halfway up the side of the meat.

Start the long cook: Put a tight-fitting lid on the casserole dish and transfer it to an oven preheated to 160°C (140°C fan). Let it cook undisturbed for 2 hours. Your kitchen will gradually fill with a deep, savoury fragrance that tells you something wonderful is happening inside that pot.

Add the vegetables: After 2 hours, remove the pot from the oven and add the carrot chunks and potato halves, pushing them down into the liquid so they're mostly submerged. The meat should look tender enough that a fork slides in with only slight resistance. Replace the lid and return to the oven for another 1 hour 15 minutes.

Thicken the gravy: Carefully lift the beef and vegetables onto a serving platter and cover loosely with foil. Place the pot on the hob over medium heat. Whisk in the cornflour slurry and let it bubble for 2-3 minutes until the gravy thickens to a silky, coat-the-spoon consistency. The colour should be a rich mahogany brown, and the texture should feel smooth when you stir it.

Rest and serve: Let the beef rest for 10 minutes before slicing against the grain into thick pieces. Spoon the gravy over the meat and vegetables. The beef should pull apart easily with a fork, and the carrots should be tender enough to cut with the side of your spoon.