Cut the potatoes into approx. 1 cm cubes, finely dice the streaky bacon, finely dice the onions, finely chop fresh mushrooms or drain 1 small can of mushrooms, put everything in a roasting bag, season with pepper, oregano and a little salt, add butter, Close and shake the bag, pierce a hole at the top.
Baking: in a preheated oven at 200 degrees (convection 160 degrees) for approx. 50 min.
CAUTION: The grid must not be preheated, otherwise the bag may burst. Sprinkle with parsley before serving.