01 - Place the diced potatoes in a saucepan and cover with cold water. Add a pinch of salt, bring to a boil, then reduce heat and simmer for 4–5 minutes until just tender. Drain well.
02 - In a large nonstick or cast-iron skillet, heat the butter and olive oil over medium heat until the butter melts and begins to shimmer.
03 - Add the chopped onions and bell pepper (if using) to the skillet. Sauté for 3–4 minutes until softened and fragrant, stirring occasionally.
04 - Add the drained potatoes to the skillet. Cook, stirring occasionally, for 6–8 minutes until they start to turn golden and develop crispy edges.
05 - Stir in the diced corned beef. Spread the mixture evenly across the skillet and press down lightly with a spatula. Cook undisturbed for 4–5 minutes to develop a crispy bottom crust.
06 - Stir the hash, flip portions, and press down again. Allow to cook undisturbed for another 3–4 minutes until additional crispy spots form throughout.
07 - Season the hash with salt and black pepper to taste. Sprinkle with fresh chopped parsley just before serving.
08 - If serving with eggs, heat a separate pan over medium heat and fry the eggs to your desired doneness. Place directly on top of the hash when serving.