Prepare the potatoes. Preheat oven to 425°F. Place potatoes on a baking sheet, pierce potatoes several times with a fork to allow steam to escape as they cook, and bake for 45-60 minutes until fork tender. Once they are cooked, remove the potatoes from the oven and cut them in quarters alowing them to release steam and cool. When they are cool enough to handle peel off the skins.
Make the dough. Place the flour on a large work surface and make a well in the middle. While the potatoes are still warm, use a potato ricer to process the potato flesh into the well. Then, make a well in the middle of the riced potatoes and add the egg yolks and salt. Using a dough scraper, combine all of the ingredients. When the dough starts to look like small pebbles, knead with your hands until the dough is smooth and homogenous. Then, cover the dough and let it rest for at least 5 minutes.
Shape the gnocchi. On a flat work surface, cut the dough into quarters. Working with one quarter at a time, roll the dough into a long log, about 1/2″ thick. Then, using the dough scraper or a knife, cut the log into pieces about 1/2″ each, creating gnocchi pillows, or gnocchi lisci, (without the charactreristic grooves).
To create the grooves, use a cavarola or gnocchi board or the back of a fork. Roll the dough into a ball, then press it firmly into a well floured gnocchi board to create the ridges, and then roll it down the board so it curls into its characteristic shape. Repeat process until you have used up all the dough.Tip: To prevent the gnocchi from sticking to the board, press firmly into the board as you begin and then ease up the pressure as you roll the gnocchi off the board. To refrigerate Gnocchi can be left at room temperature for about 30 – 60 minutes before they begin to get sticky. Any longer than that, I suggest you transfer the tray to the refrigerator, cover and chill for up to 3 hours. To freeze: Place the gnocchi in a single layer on a baking sheet, and place the tray in the freezer for about an hour, until the gnocchi are solid and will not stick together, then transfer to an airtight freezer bag. Return the bag to the freezer. Fresh gnocchi can be stored for up to 3 months or longer.
