Zucchini and Leek Soup

1 big zucchini, 1 tablespoon sunflower oil, 750 g cold water, 1 Maggi Mix for Leek Cream Soup, 1 box Garden Cress, 125 g plain yoghurt

Peel and cut the zucchini in cubes, saute them in oil, add the water and the soup mix, boil for 10 minutes. Puree everything, add the cress and yoghurt. Serve warm with croutons.