Bring vegetable soup to a boil in a saucepan. Add oat flakes. Cook for approx. 15 minutes to a thick porridge. Stir from time to time. Season with salt and pepper.
Wash parsley and chives and pat dry. Peel the onion. Drain the mushrooms.
Chop everything and stir into the oatmeal with the flour. Allow to cool.
With moistened hands, form small, flat fritters.
Heat butter in a frying pan. Fry the patties in it until golden brown on each side.