Heat the butter over medium heat in a large skillet. Add the onion and cook until it starts to soften.
Add the garlic and potatoes and stir to combine. Cook everything together for 8 to 10 minutes until the potatoes begin to get crispy and golden.
Add the corned beef, oregano, Worcestershire sauce, and a pinch of salt and pepper. Carefully stir to combine.
Cook for 8 minutes, pressing down the mixture and tossing occasionally. You don't want to stir too much, opting instead to get all the ingredients crispy and brown.
Make 4 wells in the corned beef and potato mixture and crack an egg in each one.
Cover the pan and let cook for around 3 minutes, until the eggs are done to your liking.
Garnish with fresh parsley if desired. Serve directly from skillet.