Peel the potatoes and cut into small cubes. Cut the broccoli into small pieces. Peel the onion and cut into small pieces.
Sweat the onion pieces in a saucepan in hot oil over medium heat for 4 minutes. Then add the water and the potatoes and broccoli. Boil. Add a cube of vegetable stock and, if necessary, salt. Cook on medium heat for 10 minutes. Then add marjoram, caraway seeds, garlic, pepper and the cream substitute. Cook for about 10-15 minutes, stirring often. At the end, puree everything with a hand blender.
Note: vegetable stock cubes from Knorr or Maggi are not vegan!