Peel the onions and cut into small cubes. Wash the rocket and cut into small pieces. Wash, peel and thinly slice the potatoes.
Steam the onion in the margarine until translucent, deglaze with the vegetable stock, add the potato slices and let simmer for about 12 minutes. Now add the finely chopped rocket and after another 3 minutes pour in the cream and puree everything with the hand blender.