Peel the potatoes and cut into cubes. Clean and wash the leek and cut into fine rings. Sauté the onion cut into small cubes in the olive oil until translucent, add the potatoes and leek and sauté briefly. Then deglaze with the vegetable stock, add the herbs and cover and simmer for about 20-25 minutes. Stirring occasionally. In the meantime, peel the carrots and cut into fine cubes. Puree the potato and leek mixture very finely with a hand blender, add the diced carrots and let simmer for another 5 minutes. Season to taste with salt, pepper and fresh, chopped parsley.