We could devour this quintessential breakfast and brunch dish every single day of the week.
Put the potatoes in a large pot and cover with water. Add a large pinch of salt and bring to a boil over moderately high heat. Cook for 15 minutes, until the potatoes are barely tender; drain. Peel the potatoes and cut them into 1-inch pieces.
In a large nonstick skillet, cook the bacon over moderate heat, turning once, until crisp, about 5 minutes. With a slotted spoon, transfer the bacon to a paper towel–lined plate. Pour off the fat.
Add 2 tablespoons of the vegetable oil to each of 2 large nonstick skillets. Add the potatoes and cook over moderate heat until they are browned on the bottom, about 10 minutes. Turn the potatoes, cover and cook over low heat until the potatoes are tender, 10 minutes.
Stir the onion and apple into the potatoes. Cover the skillets and cook over moderate heat, stirring occasionally, until the apple is tender, about 7 minutes. Add the salmon, cover and cook until heated through, about 2 minutes. Stir in the remaining horseradish glaze and the bacon pieces and season with salt and pepper. Transfer the hash to plates, top with the fried eggs and parsley and serve.