Get your can of corned beef and cut into 1cm-ish pieces or break it up by hand for a more rustic look.
Combine the Worcestershire sauce and mustard in a cup and pour over the corned beef, stir to combine.
Set this aside for later.
Slice the onion.
Wash the potatoes and cut into 1 cm cubes, leaving the skin on, place the cubes in a saucepan. Pour enough boiling water from the kettle to almost cover them, then add salt and simmer for 8 minutes with the lid on.
Drain the potatoes and set aside.
Fry the onions in the frying pan with oil until they are golden brown.
Put the heat on high, add the drained potatoes and toss these around with the onions. Add more oil if necessary.
Add the salt and pepper. Season to your taste.
Keep turning the mix, After about 6 minutes, add the beef and continue to toss everything around to allow the beef to heat through (about 3 minutes).