Peel and chop the onion. Roughly dice the beetroot (wear disposable gloves - they stain strongly!). Peel, wash and dice the potatoes. Heat the oil in a large pot. Brown everything in it. 3⁄4 Add l water and broth, bring to the boil. Cover and simmer for about 15 minutes.
Wash the herbs and shake dry. Chop the dill, cut the chives into small rolls. Puree the soup. Season with salt and pepper. Stir in 200 ml buttermilk.
Serve the soup. Garnish with 1 tbsp. buttermilk and herbs. Delicious with baguette.