Heat 1 tbsp of oil in a large saucepan with a lid. Season meat, then cook about one-third over a high heat for 10 mins until browned. Tip onto a plate and repeat with 2 tbsp of oil and rest of the meat.
Add a splash of water and scrape pan to remove bits. Add ½ tbsp oil. Turn heat down, fry onion and garlic until softened. Return meat to the pan, add flour and stir for 1 min. Add treacle, cumin, tomatoes and stock. Bring to boil, reduce heat, cover and simmer for 1 hr 45 mins. Stir occasionally and check that the meat is covered with liquid.
Add peppers and beans, and cook for a further 15 mins. The stew can now be cooled and kept in the fridge for 2 days, or frozen for 1 month. Serve in bowls, with sour cream, coriander and cornbread.