Wash and boil the potatoes in their jackets; mash and spread out on to cool on a hard surface.
When cool add flour and egg and mix to make a smooth dough. Roll out to a thickness of 1 cm.
Place cubes of cheese and the onion sautéed in butter at a suitable distance apart. Lay another layer of rolled dough, seal the edges and cut as if making ravioli.
Check that they are well sealed and cook in boiling water for 5 minutes or until they come to the surface.
Drain and serve with butter melted in a little broth and then reduced.
Recipe from the restaurant ‘Alla Pineta’