Sauté diced potatoes and other vegetables in a pot, then add bouillon or water until all vegetables are just covered. Boil for half an hour.
ingredients: 300g potatoes, 1 tbsp vegetable oil, 1 pc. each of Leek, carrot, celery root, half an onion, stock or bouillon (cube, powdered or liquid), 2 tbsp flour, cream (optional), salt and spices.
Wash the potatoes (hold them under running water while rubbing the surface with your fingers) if necessary (the wash step can be omitted if the potatoes appear clean, i.e. if their skin is smooth and no dirt particles stick to the skin) and peel them (using a vegetable peeler). Cut away any bad parts, if there remain any (zones where the potato itself is black or dark brown). Put the peeled potatoes onto a cutting board and cut them into 4-20 pieces (depending on the size of the potato; each piece should be somewhere between 5 and 25 cm3). Cut leek, carrot and onion to small pieces (< 10 cm3). To a large pot, add oil and heat until hot. Add pieces of potatoes, onion, leek celeriac and carrot and stir once per minute; put the lid on the pot when not stirring. After 5 min, distribuite 1 Tbsp of flour on top of the frying vegetables and mix immediately with several strokes. To a separate vial, add 0.5 L of tap water, 1 teasp. of bouillon (or a bouillon cube) and half a teaspoon of salt and stir this with a spoon or a fork. Add this (in one go) to the frying vegetables in the large pot and stir. In case the vegetables are not entirely covered with liquid, add more water until they are just covered. Heat at maximum but stay close: as soon as the water boils, reduce the heat to about 30% of the maximum and leave the pot on the stove with the water slightly boiling and the lid on for half an hour. Then turn off the heat and remove the pot from the stove. Use an immersion blender to chop up the pieces floating in the soup and to obtain a homogenous texture. Add pepper (several pinches), nutmeg (max. 1 pinch), cream (up to several tbsp), parsley, bits of smoked bacon, etc. as desired.