Preheat oven to 200 ° C.
Wash zucchini and cut off the ends. Halve and remove the cores.
Hollowing and dice the flesh finely. Wash the tomatoes, remove the stalk and dice also finely. Peel the onion and garlic. Dice onion and mash the garlic.
Mix all ingredients with parmesan, herbs and spices and season to taste. Fill the zucchini halves with the mixture.
Cover a gratin dish with oil, add vegetable soup and place the zucchini halves.
Bake in oven about 35 minutes.
Remove zucchini and stir sour cream into the soup.