Peel potatoes, carrots and onion, wash potatoes and carrots. Wash and clean the celery. Cut celery and carrots into diagonal slices. Halve or quarter potatoes depending on size.
Halve the onion and cut into slices. Heat the oil in a pot. Sauté vegetables and potatoes in it. Pour in broth, cover and cook over a mild heat for about 20 minutes. Wash parsley, dab dry, put some leaves aside for garnishing.
Finely chop the rest. Season stew with salt and pepper and sprinkle with parsley. Garnish with set aside leaves.