Clean the onion and chop it finely. Peel the tomatoes and dice them finely.
Braise the onion in the oil for 5 min. Then add the tomatoes to it and saute them together until the tomatoes soften. When they do, add the paprika and sugar, stir and crumble in the vegetable broth.
Dilute with 6 1/5 cups (1.5 L) water, sprinkle with the finely chopped fresh basil or dried such, and crumble in the vermicelli. Season with salt to taste and boil until the vermicelli is ready. Then remove from the heat.
For the thickening agent, beat the egg and yoghurt and add the crumbled feta cheese to them. Thicken the soup with this mixture.
It tastes best when cooled.