Finely chop the onions and fry them. Add the tomatoes and tomato pieces, fill up with 300 ml vegetable stock, bring to the boil and season with plenty of garlic, cumin powder, chilli and a little oregano and salt. Add sugar and beans and simmer for 30 minutes on a low flame.
It goes well with bread, alternatively seared tortilla. Cheese or sour cream can be served as a topping.