Start the dough by heating a medium-sized pot plenty of water and adding salt. Wash the potatoes with the whole peel (1). Add the potatoes (2) in the hot water and cook for about 20 minutes to boil it. Once boiled, drain the potatoes (3) and let it cool a little.
Placing the potatoes on a cutting board (4), and peel them with a knife (5). Put the vegetable without peel in a soup plate and mush them with a fork, or a potato masher (6), to have a smooth mixture without lumps.
Now, on a wooden worktop, sift the white flour (7) over the mash potatoes. Then break the whole egg (8) in a bowl, to identify any pieces of shell and eliminate them. Then pour the whole egg on the flour and potatoes (9).
Now start kneading everything (10) with your hands, until you get a soft and elastic dough (11), without lumps. Let rest for about two hours, so that it dries a little. Finally take it back and then start cutting it into small pieces (12).
Take a small portion and form a cigar on a cutting board with the palm of your hands (13). Thickness need be about one and a half centimeters. Made the cigar, start to cut it into squares with a thickness of two centimeters (14), repeating the same operation for the remaining dough. Then make the lines with the tines of the fork (15) for all the gnocchi. Put the gnocchi aside on the wooden surface, sprinkle with flour and begin to prepare the sauce.
Wash the leek (16) and chop it finely (17) to leave aside on a saucer (18).
Wash the carrot (19), dry and grate it (20) to leave in a saucer (21).
Wash the celery stalk well (22), dry and chop (23) it. Leave it aside on a saucer (24).
Now pour five tablespoons of extra virgin olive oil (25) into a large pan. Heat over medium fire. then add the chopped leek (26) and grated carrot (27).
Add the celery (28) and fry for a couple of minutes, stirring with the spoon (29). Then add the tomato sauce (30).
Mix well (31) and cook for ten minutes. Then add some salt (32) and mix again, to cook another ten minutes. Meanwhile grate the Parmesan (33).
Once done, add the Borlotti beans (34), after having drained them. Mix (35) in the sauce and let them heat a few minutes over low heat. Meanwhile put a pot plenty of salted water. Once the water is boiling dip in the gnocchi (36) to start cooking.
When the gnocchi come to the surface, after a couple of minutes, take them directly from the water with a copper (37), drain them a few seconds, and then add directly in the pan (38) with the sauce. Mix well (39) with extreme delicacy.
Now sprinkle with Parmesan (40) and some freshly ground black pepper (41). Stir again (42) and serve immediately on the table, very hot.