1Cook the potatoes in water for 20 minutes until soft, drain them, and add a little salt.
2Mash them very well until there are no lumps.
3In a hot pan, fry the bacon until golden brown.
4Meanwhile, whisk three egg yolks, a little salt and pepper, a cup of Parmesan cheese, a little of the oil left over from the bacon, and a little warm water with a whisk to achieve the right texture.
5Serve the mashed potatoes over the carbonara with the bacon and a little chives.