Drain potatoes and remove peel with a knife while they're hot, being careful not to burn your fingers. With a potato ricer, mash potatoes on a clean surface. Form a well in the center of mashed potatoes and break an egg in it. Add cheese, nutmeg and two pinches of salt (or more if needed). Combine all ingredients and gradually add flour - just as much as the dough takes. Depending on the type of potatoes you're using, you'll need more or less flour. The secret to soft gnocchi is to hold back on flour and stop kneading as soon as you get a workable dough. Once you obtain it, divide it in pieces with a dough cutter (see photo).
Lightly dust the working surface with flour and roll each piece into ½-inch logs. Using the dough cutter, cut each log into small pieces.You can boil a small batch to test the consistency and adjust the amount of flour, if needed.
Toss gnocchi in boiling water. Once they come to the surface (it'll take about 2 minutes), transfer them with a slotted spoon into a pan containing the sauce and turn on heat.