Season 1.8kg of beef chuck roast with salt and pepper and dust lightly with flour. Brown on all sides in a little olive oil in a large Dutch oven.
Add water to surround the meat without covering it. Add 1 sliced onion, 5 chopped garlic cloves, and 1 green bell pepper, cut into chunks. Cover and simmer for about 2 hours, until fork-tender.
Lift out the beef, let it cool, and shred it. Discard the vegetables and cooking liquid.
Heat a little olive oil in the pot and sauté 2 chopped onions, 2 chopped green bell peppers, and 4 crushed garlic cloves until limp.
Stir in 115g of tomato paste, 900g of canned crushed tomatoes, 2 tablespoons of ground cumin, 1 cup of red wine, 1 bay leaf, and the beef.
Cover and cook over low heat for about 30 minutes, stirring occasionally. Remove the bay leaf.
