The first thing you must do is buy old potatoes - those with a thick skin so you definitely don't want to buy new potatoes or those modern varieties that are covered in a fine veil of a skin. Then cook the potatoes whole so they don't absorb as much liquid - you want them as dry as possible. Alternatively, you can cook whole potatoes in the oven and this is what I did so there was no risk of a watery potato mash.
Then the potato mash must be cold before you mix it with the flour. I remember last time I was mixing the dough I was practically burning my hands the potato was so hot.Put the flour on the table and add the salt and potato. Mix in the egg yolks then mix until you have a soft ball. Do not overwork the dough. As soon as it sticks to your hands, stop! Gnocchi is a very delicate dough and the less you work it, the softer your gnocchi will be.
Cut a small piece of dough and roll it with the palm of your hands until you have a long thin cylinder. Cut it with a knife using a little flour if necessary. Give the gnocchi the proper shape and cook them in salted boiling water straight away. (If you leave the gnocchi in the fridge uncooked, they will start to get soggy and gluey).
If you make the gnocchi the day before required, you can cook it then strain it and then cool in water and ice. Dry them with a cloth and store them in a container with a bit of olive oil. This way you will be able to keep your gnocchi cooked in a the fridge for a couple of days. When you want to have them, just tip them into boiling water until they rise to the surface.
Recipe by Hotly Spiced at http://hotlyspiced.com/how-to-make-gluten-free-gnocchi/