Arrange all ingredients for use.
Peel and finely dice the onion and garlic.
Halve and deseed the chillies, then finely chop.
Pour the oil into a deep pan and fry the minced meat until browned, breaking up with a spoon.
Add the onion, garlic cubes and chilli and mix. Cook for 2-3 minutes then add the tomato puree and cook briefly. Pour in the stock.
Wash the tomatoes, cut out the stalks and roughly chop the flesh.
Add to the chilli and simmer gently, half-covered, for 1-1 1/2 hours.
Finely chop the oregano leaves.
Occasionally stir the chilli and add stock if needed.
Wash the beans and drain well. Add to the chilli about 15 minutes before the end of the cooking time.
Add the oregano to the chilli and season with salt.
Season with sugar and pepper to taste. Serve in bowls garnished with sour cream, chilli and tortilla chips.