First of all, cook the potatoes: wash them well, put them in 1 pot, cover with plenty of cold water, bring to the boil and cook for about 30 minutes, then peel them, mash them with a potato masher and add salt, pepper and Parmesan cheese.
In the meantime that the potatoes are cooking, get on with the work and prepare the sausages: remove the casing, then brown them for a few minutes in a non-stick pan, without oil.
Then proceed to the preparation of the meatballs: with wet hands, take a little of the potato mixture, flatten it on the palm of your hand, stuff it with a little sausage and a cube of cheese and close it into a ball on the filling.
Then pass the meatballs first in the lightly beaten egg and then in the breadcrumbs.
Once you have all the meatballs, fry them in hot seed oil, turning them to brown them evenly, and then drain them on kitchen paper.
(Alternatively, arrange them on a baking sheet lined with parchment paper and cook them for about 20 minutes in a convection oven preheated to 200 ° C.)
The meatballs, potatoes and sausage are ready, serve them immediately.