Preheat the oven to 350 degrees. \nNote: If your potatoes are not already cooked, place them to a pot of salted water and bring to a boil. Boil until just fork tender, about 5-7 minutes. Drain, pan to dry, and cut into ½-inch cubes. Set aside. \nMelt the butter in a large skillet over medium heat. Stir in the onion and season with a pinch of salt. Sauté, stirring occasionally, until softened and translucent, about 5 minutes. \nAdd in the corned beef, potatoes, Grillville spice and ½ teaspoon salt, mixing to combine. Spread into a single layer in the pan. Let cook, undisturbed, over medium\/medium-high heat until golden brown on the bottom side, about 5 minutes. Give the mixture a toss and continue cooking until golden brown and crispy on both sides, about 3-5 minutes more. \nRemove from the heat and, using the back of a wooden spoon, make 4-6 indents into the hash. Crack an egg into each of the holes. Season with a pinch each of salt and pepper. Transfer to the oven and bake until the whites are set but the yolks are still runny, about 3-5 minutes. \nIf using, toss the cabbage with a drizzle of olive oil and a pinch each of salt and Grillville spice. Set aside, allowing the cabbage to soften, until ready to serve. \nCarefully remove hash from the oven. Top with cabbage slaw and fresh parsley leaves. Dig in!