Rinse beans and drain well. Peel and finely chop the onion. Wash the thyme and chop coarsely.
Fry the onion in 2 tbsp. hot oil. Sweat tomato paste briefly. Add the chopped tomatoes and 5-6 tbsp. water. Season with salt, pepper and 1 pinch of sugar. Bring the sauce to the boil and simmer open for about 10 minutes.
Add the beans and thyme to the tomato sauce and bring to the boil. Simmer for about 2 minutes. Season to taste again. Let the beans cool down and sprinkle with 2-3 tbsp. oil before serving.