Boil the potatoes and mash them when they are still hot.
Put them aside and let them cool off
In a large bowl beat the egg, add the potatoes, the flour and the salt.
\Mix very well until you have a firm ball of dough. If the dough is still soft, add more flour until you have a firm consistency.
Wrap the ball of dough in plastic paper and let it sit for about 30 mins.
With the Nonna Knife, cut a piece of dough, roll it into a strip about 1/2" tick and cut it into pieces about 3/4" long.
Take each piece of dough put it on a Gnocchi board, if you would like some texture, and with the tip of two of your fingers, roll the dough toward you.
Make all your Gnocchi, boil them in salted water and serve them with your preferred sauce.