Preheat the oven to 170°C (fan on).
Heat 1 tsp of olive oil in a large cast-iron casserole. Add the beef pieces and sear them on all sides. Remove the beef from the casserole and set aside.
Add the butter and chopped onions, and cook for 3–4 minutes until softened. Add the chopped garlic and cook for 1 minute until fragrant. Stir in the plain flour, tomato purée, and all of the seasonings.
Return the beef to the casserole along with the halved potatoes. Stir well, then pour in the water. Add the bay leaves and vinegar, mix again, cover with a lid, and bring to the boil over high heat. Transfer to the oven and cook for about 1 hour.
Carefully remove the casserole from the oven. Add the peppers and tomatoes, stir gently, cover again, and return to the oven. Continue cooking for another 1–1½ hours, or until the beef is tender. Cook longer if needed.
Garnish with chopped parsley and serve with rice or crusty bread.
