The dish is best prepared in a wide cast iron casserole. Cut the raw potatoes into 2 cm cubes and fry openly in half butter, half oil (butter so that they brown, oil so that the butter does not burn). Do not salt!
In the meantime, peel two small onions and cut into crescents. Add and fry while stirring without a lid, then cover and cook for a few more minutes on a slightly lower heat.
Then you clear a small area in the pot and sweat the roughly diced bacon sausage there briefly. Now everything is seasoned with salt and marjoram (and possibly caraway seeds), turned and cooked covered over a low heat for about 10 minutes until the whole thing is cooked through and well done.
If the dish gets too dry, add a small amount of water. Broth is not necessary! Sprinkle the Gröstl with parsley and serve with fried eggs and pickles.