Preheat oven to 375°F. Wash the potatoes and wrap tightly in foil. Place the potatoes on a baking stone or sheet pan and bake for 90 minutes or until soft. Remove from the oven, unwrap immediately and cool until easily handled (but still somewhat warm.)
Peel the potatoes and discard the skin. Press the warm, cooked potatoes through a ricer onto a clean work surface, or gently mash.
Add the ricotta cheese to the pile of riced potatoes and gently work in just until lightly distributed. Add the flour and a pinch of salt and gently fold together until combined. Don’t smash the potatoes, but mix with your hands using a gentle folding method. Make a well in the center of the potatoes and add the lightly beaten egg. Work in the egg and continue mixing to form a soft smooth dough. Be careful not to overwork the dough! The dumplings will end up dense and won’t expand when cooked if it’s overworked.
In the meantime, bring a large pot of water to a boil. (SEE NOTE BELOW)
Cut the dough into 4 equal pieces. Working with one piece at a time on a lightly floured work surface, roll the dough into a log about ¾-inch in diameter. Flour a table knife or kitchen scraper and cut each log into ½-inch to ¾-inch gnocchi pillows. To shape the gnocchi, either press gently in the center with your finger or roll down the back of a fork (see video) to make ridges.
Once the water is boiling, reduce the heat just a little and add some of the shaped gnocchi. Be sure you don’t crowd the pot - so cook in batches depending on the size of your pot. The gnocchi cooks quickly, in about 2 minutes, and rises to the top of the water when done. Remove the floating gnocchi with a slotted spoon and transfer to a clean, dry baking sheet to dry while cooking the remaining dough. When cooked, the gnocchi should puff up or swell and have a pillowy soft texture when eaten.
Serve and enjoy!