Wash and scrub the potatoes thoroughly. Make sure to remove all dirt but leave the skins on.
In a large pot, put enough water to cover the potatoes when they are placed inside and bring to a boil.
Boil for 25-30 minutes, or until the potatoes are soft enough so that they can be pierced easily with a fork.
Drain the potatoes and remove the skin while they're still warm. If you have a potato ricer, you don't need to peel them.
Using the potato ricer, mash the potatoes. Make sure to get rid of clumps but don't over-mash. If you don't have a potato ricer, mash the potatoes with the help of a fork (after removing the skins).
Let the potato mixture cool enough to handle. If you are not using the egg, let them cool for at least 30 minutes so they are chilled completely.
To make the dough, in a large bowl combine the mashed potato and flour.
Add the slightly beaten egg and mix into the potato and flour. Then, add a pinch of salt.
Knead the ingredients together very briefly, just until you get a soft but firm uniform dough. Do not over mix.
Once you get the right dough consistency, remove an eighth of the dough and cover the rest of the dough so it doesn't dry out.
On a lightly floured surface and with some flour on your hands, roll the piece of potato gnocchi dough under your hands until it forms a long rope as thick as your thumb.
Cut the rope into pieces of about 1-in/2-cm, separating the gnocchi from each other.
Repeat the procedure until you have used all the dough to make 2-cm gnocchi.
If you have gnocchi board
If you have gnocchi board, you can use it to make ridged gnocchi. To do so, use your thumb (or forefinger and middle finger together), press and roll each gnocchi gently downward to form the ridges. Do not push too hard or the gnocchi will be misshapen.
If you don't have a gnocchi board
If you don't have a gnocchi board, you can use a lightly floured fork to make the ridges. Dip a fork in flour and using the back of the tines, slowly roll the gnocchi down the back of the fork tines by applying gentle pressure with your thumb. Although you can leave them smooth, we recommend making the ridges on the little dumplings because the sauce clings much better to them.
Place the finished gnocchi on a lightly floured cutting board or tray. Leave to air dry for about 20-30 minutes. If you did not use egg, this step is extremely important when making your gnocchi, so you should leave them an additional 20-30 minutes.
To cook the gnocchi, put a large pot of water on the stove and bring to a boil. Add salt to the water.
Gently place the gnocchi dumplings into the boiling water and stir gently to make sure they don’t stick together.
Boil them for about 2 minutes, but not more than 3. When the dumplings start to float in the boiling water it means they’re almost done. Just give them another 25 seconds before removing.
Remove them with a slotted spoon or small hand-help strainer and put them directly into the pan with the sauce you have prepared.
The easiest sauce is a 1/2 stick of melted butter or 1/2 cup of olive oil heated with 5 sage leaves in a large sauce pan until the sage gets a little crispy and the butter slightly browns. Once you have stirred the gnocchi in, top with Parmesan cheese, Parmigiano Reggiano or Grana Padano and serve immediately.