Peel, cut potatoes into even chunks, and boil in salted water for 5 minutes until tender. Drain, put back in the pan, and cover to steam.
Slice the onion and fry gently in oil until softened and golden.
Tip in the drained potatoes, breaking them up lightly with a spoon, and fry until beginning to crisp.
Stir in the Worcestershire sauce, mustard, salt, and pepper.
Cut the beef into small cubes, stir through the potato and onion, and cook for a few minutes until heated through.
In a separate pan, fry the eggs to your liking.
Spoon the hash onto plates and top each portion with a fried egg.
