Peel the onion and cut it into small cubes

Put the oil in a thick-bottomed pan and heat up

Add onion and sauté until it takes on color

Pour in the tomatoes and bring to the boil

Add the green beans and let the dish simmer until the beans are tender after approx. 5 minutes.

Season the tomato sauce with sugar, salt and pepper.

Cool the dish and serve it cold.