Clean the mushrooms thoroughly and finely chop them.
Heat a little oil in a frying pan. Add the chopped mushrooms and sauté until softened and any excess moisture has cooked away.
Transfer the mushrooms to a bowl and allow them to cool slightly.
Add the egg, flour, a little softened or melted butter, and salt.
Mix everything together until the mixture holds together well enough to shape.
Divide the mushroom mixture into 5–6 portions and form each into a small schnitzel or oval patty.
Coat each mushroom schnitzel in breadcrumbs.
Heat a little oil and butter in a frying pan over medium heat.
Fry the schnitzels until golden brown and crisp on both sides, approximately 3–4 minutes per side.
Serve immediately while hot and crisp.