Lightly wash the mince if you wish. drain excess water on a fine slotted colander and set aside
Heat oil in a deep pot/wok and fry the onions till they turn translucent. Add the chopped garlic, green or red chilli and bell pepper (if using), fry for half a minute.
Add the minced beef, chilli powder, cumin powder, oregano and fry for 2-3 minutes.
Add the stock and the canned (or fresh) tomatoes. Mix well, add salt to taste, check the taste and add the tomato puree (only as much as required)
Reduce the heat to a simmer and cook for 15-20 minutes, then add the kidney beans (or if they are already overcooked, add them during the last 5-10 minutes of the cooking stage. Continue to cook for another 20-25 mins or till the meat is very well done. Stir in between to avoid scorching. The cooking time may vary according to the quality, tenderness and the cut of the minced meat (how finely it has been minced)
Remove the pan from heat, garnish with finely chopped onions or chopped fresh coriander and serve hot with steamed white rice