Boil potatoes, peel, let cool and cut into slices. Chop cooked beef coarsely. Chop onion finely.
Heat oil in a large frying pan and fry onion.
Add potatoes, season with pepper, salt, caraway and marjoram. Fry until golden brown and crispy, turning frequently. Add beef.
In a separate pan, heat some butter, crack eggs and fry fried eggs.
Serve the fried eggs on top of the Gröstl.