How to Make It
Heat a large nonstick skillet. Rub the fish all over with the oil and season with salt and pepper. Place 1 fish in the skillet, skin side down, and cook over moderately high heat until the skin is golden, about 3 minutes. Add 3 tablespoons of the butter and cook over moderate heat, basting the trout constantly, until the skin is crisp and the flesh is just white throughout, about 2 minutes. Transfer to a plate. Add 2 tablespoons each of the butter and capers to the pan and cook, stirring, until the butter is deep golden, 1 to 2 minutes. Season with salt and stir in 1 tablespoon of the parsley. Spoon the brown butter sauce over the fish. Repeat with the remaining fish, butter, capers and parsley. Spoon beet horseradish over the trout and serve.