Place the beef on a board and lightly score one side.
Bash the cinnamon, cumin, paprika and oregano in pestle and mortar, then rub into the cuts in the beef. Season well with sea salt and black pepper, drizzle over a little oil and brown the brisket well in a large pan over a high heat.
Place the bay leaves, whole peppers, plum tomatoes (breaking them up with the back of a spoon as you go), and the stock in a large pot and bring to the boil.
Meanwhile, deseed half the chillies, then finely slice them all. Peel and finely slice the onions, then pick and finely chop the coriander.
Add the chilli and onion to the pan with the brisket, cook for 5 minutes, then transfer the lot to the large pot, cover, and leave to simmer for 4 to 4½ hours, or until beautifully tender, stirring occasionally and adding splashes of water to loosen, if needed.
Gently pull the beef apart using 2 forks. Remove the bay, add a little vinegar to taste, scatter over the coriander and adjust the seasoning to taste.