01 -
In a pan, sauté onion and mushrooms in butter until soft. Season with salt, pepper, and parsley. Let cool.
02 -
In a bowl, mix mashed potatoes, flour, egg, salt, and pepper until dough forms.
03 -
Take a portion of potato dough, flatten it, place 1–2 tablespoons of mushroom filling (and cheese if using) inside, and cover with more potato. Shape into patties.
04 -
Lightly coat patties with breadcrumbs. Heat oil in a skillet and fry until golden brown on both sides.
05 -
Enjoy warm with sour cream or a squeeze of lemon for brightness.