Preheat the oven to 160°C (325°F/Gas Mark 3).
With a sharp knife, make several 2.5 cm-deep slits all over the topside of beef.
Cut the Spanish chorizo into small strips or 1 cm cubes and push them into the slits.
Generously season the beef with salt and black pepper.
Heat the olive oil in a large, flameproof casserole dish over medium-high heat until shimmering.
Sear the beef on all sides until deeply browned, about 3–4 minutes per side, then transfer to a plate.
Reduce the heat to medium and add the chopped onion and green pepper. Cook for 5–7 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Pour in the dry white wine, scraping up any browned bits with a wooden spoon. Simmer until slightly reduced, about 2 minutes.
Stir in the chopped tomatoes (including their juice), beef stock, ground cumin, dried oregano and bay leaves. Bring to a gentle simmer.
Return the beef to the casserole, ensuring it’s mostly submerged. Cover with the lid.
Transfer to the oven and cook for 3 to 3½ hours, or until the meat is fork-tender.
Remove the beef and leave to rest on a board for 15 minutes.
Skim off any excess fat from the sauce, if you like.
Thinly slice the beef, spoon over the sauce and serve.