1) Boil the potatoes in their skins for 5 minutes, drain and peel them. With the help of a digger, make a hollow of suitable size to contain the egg, in the central part of the potatoes. Grease them with a little oil, salt them, arrange them on a baking sheet lined with parchment paper and bake at 180 ° for 10 minutes.
2) So, shelled 1 egg inside the recesses of the potatoes, season with salt, pepper and 1 flake of butter and bake again for 2 minutes, so that the egg white is firm. Serve the very hot potatoes, sprinkled with sliced ​​truffles.