Peel the Jerusalem artichoke and cut into slices. Peel and dice the onion. Wash and slice the carrots. Roughly dice the tomatoes.
Sauté the onion in oil and add salted water or broth. Add tomatoes, carrots and Jerusalem artichoke and simmer for about 10-20 minutes (depending on the pieces). Then puree and season with sugar, salt, pepper and chilli.