Clean or peel the soup vegetables, rinse and cut into small cubes or rings. Peel and rinse the potatoes and also cut them into small cubes. Peel and finely dice the onion.
Heat the oil in a saucepan and briefly sauté the soup vegetables, potatoes and onions while stirring. Then add the pearl barley and steam with it. Pour in the vegetable stock and add the bay leaf. Let everything simmer over a low heat for about 30 minutes.
Rinse the parsley, shake dry and finely chop the leaves. Season the soup with salt and pepper and fold in the chopped parsley.