Peel and finely chop the onion. Clean, wash and roughly dice the potatoes, celery and beetroot. Quarter cabbage and cut into narrow strips. Wash cucumber (peel if necessary), cut in half lengthwise.
Scrape out the seeds with a teaspoon. Cut the cucumber into thick slices. Heat the oil in a large pot and lightly fry the vegetables, except the cucumber, in it. Fill up with broth and vinegar.
Season lightly with salt, pepper, caraway and honey. Cook at medium heat in a closed pot for about 45 minutes. Add the cucumbers 15 minutes before the end of the cooking time. Roast sunflower seeds in a dry pan until golden brown.
Pour onto a plate and set aside briefly. Wash the parsley (put something aside for garnishing) and chop finely. Season the stew again. Mix sour cream. Pour into a small bowl and sprinkle with parsley.
Fill out soup. Fill a tablespoon of sour cream in the middle. Sprinkle with roasted sunflower seeds.