Cut onion into small pieces, chop garlic finely and fry them together in a pan in vegetable oil, stirring, for 1 minute.
Cut carrot into thin slices, add them to the onion with the garlic in the pan and stir-fry for 3 minutes.
Cut pickled cucumber into slices, add them to the vegetables in the pan as well and stir-fry everything for 1 minute.
Cut mushrooms and oyster mushrooms into pieces, add them to the other ingredients in the pan and stir-fry for another 3 minutes.
Add tomato paste, stir fry everything for another 3 minutes and then set aside.
Peel and cut into cubes potatoes, boil them in a saucepan in 1.5 l water for 5 minutes.
Cut cauliflower into small pieces, add it to the potatoes in the saucepan and cook it for another 5 minutes.
Add the sautéed vegetables from the pan and cook the soup for another 5 minutes.
Cut olives in half and parsley into small pieces. Add both to the soup in the saucepan along with the lemon slice and bay leaves, season the soup with salt and pepper, and cook for 3 more minutes.