Potatoes in Surprise

Wash and brush medium-sized potatoes, wrap them in separate sheets of damp paper; range on a baking tin, and cook in a slack oven for thirty to forty minutes; remove, unwrap and make an opening on one side of each potato; empty the contents with a small spoon, pound this to a pulp with fresh butter, salt, nutmeg and egg-yolks; refill the potatoes, close the aperture with the piece removed, and lay them on a buttered baking tin, having the opening uppermost. Push into a slack oven for twenty minutes, then dress on or inside of a folded napkin.