Peel and dice the potatoes and onions. Clean the leek and cut into rings.
Heat the oil in a large saucepan and sweat the vegetables in it. Add the vegetable stock and simmer for about 20 minutes. Take the pot off the stove and puree everything with a hand blender. Then add the brunch and heat again. Season to taste with salt and pepper.
Tip: Salmon strips or bacon cubes are also delicious.