Heat the oil in a large cast iron potije over hot coals, or in a heavy-based pot on the stove, and fry the onion, garlic and leeks until soft.
Add the beef cubes and fry until well browned.
Add the red wine and tomato paste, stir well, then allow to simmer until reduced by almost half.
Add the carrots, mushrooms, mielies, thyme, Knorr Beef Stock Pot and water. Do not stir your pot – allow the vegetables to sit in layers on top of the meat.
Simmer with the lid on for 1½ to 2 hours, or until the beef is tender.
About 10 minutes before serving, mix the contents of the sachet of Knorr Rich Beef and Tomato Soup with some water to make a smooth paste, then stir into the potjie together with the green beans. Simmer until the green beans are tender and the sauce has thickened.