In a shallow dish, season the flour with salt and pepper and whisk to combine. Pour the beaten eggs in a second shallow dish. Combine the bread crumbs and hazelnuts in a third dish.
Add the parsley to the mashed potatoes and season them with salt, pepper, and nutmeg. Roll the potatoes into 1-inch balls. Dip a ball into flour, then egg, and finally into the bread crumb-hazelnut mixture, and set it on a wire cooling rack. Repeat with the remaining potato balls.
Pour the Graisse de Canard Gold® into a nonstick skillet to a depth of 1/2 inch. Heat the duck fat over medium-high heat until hot but not smoking. Add the potato balls, a few at a time, to the hot fat and fry until they are a rich golden brown, turning to color them on all sides. Remove them from the pan, drain on paper towels, and serve, or keep warm in a slow (250°) oven.
