01 - Place cubed potatoes in a saucepan and cover with cold water. Bring to a boil over medium-high heat, then reduce to a simmer and cook for 5–6 minutes until just tender but not mushy. Drain and set aside.
02 - In a large skillet, heat 1 tablespoon butter and 1 tablespoon oil over medium-high heat. Add the potatoes and cook for 8–10 minutes, stirring occasionally, until golden and crispy.
03 - Push potatoes to the side of the skillet. Add remaining butter and oil, then add onions and bell pepper. Sauté for 3–4 minutes until softened.
04 - Add corned beef to the pan, mixing everything together. Spread mixture evenly in the skillet and press down gently. Cook undisturbed for 3–4 minutes to develop a crispy crust.
05 - Stir and flip the hash, then press down again. Cook for another 3–4 minutes until the other side is crispy.
06 - Taste and season with salt and pepper as needed. Top with fried or poached eggs if desired and garnish with chopped parsley. Serve hot.