Wash and dice zucchini. Peel onions, garlic cloves, carrot and potato. Slice onion and garlic cloves, dice potato and grate carrot.
In a soup pot heat a spoon of olive oil, then add onions and stir-fry until translucent. Add garlic, carrots and potatoes and stir-fry for about a minute, then pour in about half of the vegetable stock, bring to a boil, then reduce heat and let it simmer for about 10-15 minutes, or until the potatoes are almost cooked.
Then, add in diced zucchini, the remaining stock, season to taste with salt and pepper and let it cook another 5 minutes, so the zucchini get tender, but not overcooked.
Remove from heat and blend into a smooth soup with a stick blender. Then add in chopped fresh herbs, pour into bowls and add a teaspoon of sour cream into each bowl. Serve hot.