01 - Bring a medium pot of salted water to a boil. Add diced potatoes and cook for 5 to 7 minutes until just tender. Drain thoroughly and set aside.
02 - Heat butter and olive oil in a large skillet over medium heat. Add onion and bell pepper; sauté for 3 to 4 minutes until softened and fragrant.
03 - Add the parboiled potatoes to the skillet. Cook for 5 to 7 minutes, stirring occasionally, until they begin to develop golden edges.
04 - Fold in diced corned beef. Press mixture into an even layer and cook undisturbed for 5 minutes to form a crisp crust. Flip in sections and cook another 3 to 4 minutes until browned.
05 - Season generously with salt, pepper, and fresh parsley. Reduce heat to low and keep warm while preparing eggs.
06 - Fill a saucepan with 2 inches of water. Add vinegar and bring to a gentle simmer. Crack each egg into a small bowl, then gently slide into the water. Poach for 3 to 4 minutes until whites are set but yolks remain runny. Remove with a slotted spoon and drain briefly.
07 - Divide hash among warm plates. Top each portion with a poached egg. Garnish with additional parsley and serve immediately.