As chef Jim Burke describes, this decadent dish is "immensely satisfying" to make. It’s simple and straightforward, but so creamy and indulgent that you may find yourself getting lost in the meal (and hopefully forgetting what day it is altogether).
Preheat the oven to 350 degrees.
Wash the potatoes well and poke holes all over them. Season them generously with salt and bake for approximately 1 ½ hours, until very soft. Split them down the middle and open them slightly. Leave them in the oven with the door ajar for an additional 10 minutes to dry them out. Once you take them out of the oven, you must work quickly.
Scoop out the cooked potato and put through the food mill/potato ricer one time (be sure not to overload at any given time or it will work the potato too much, just do 1 potato at a time). Add the egg, flour, cornstarch, and a big pinch of salt. While still very warm, work all of the ingredients together into a homogenous dough. Be sure to stop the moment the dough comes together, as working the dough too much will develop the gluten and make the gnocchi very dense and heavy.
Cut the dough into pieces the size of your fist and roll them out to even ½-inch thick cylinders. Once they’re all rolled, line them up, generously flour them, and cut into ¾-inch lengths. Once they are all cut, the last move is to roll them over a fork to give them their characteristic shape. Place the piece of gnocchi, 1 at a time, on the back of a fork. With your thumb, press down gently to create a dimple in the gnocchi and ridges on the opposite side. Then roll the gnocchi over itself and down the fork.
At this point the gnocchi can be used right away or frozen. These gnocchi would go wonderfully with your favorite pasta sauce. At the restaurant, we toss them with a black truffle, Alfredo sauce, and Parmesan cheese and brown them under a broiler until golden brown.