In a bowl, mix together the cheese, the prunes (stoned and chopped into pieces), a pinch of salt, a pinch of sugar and a sprinkling of cinnamon. Mix well and put to one side.
Boil and peel the potatoes and then mash them directly on the kitchen work surface. Add salt, sprinkle with flour and add the egg, a little nutmeg and the butter. Use your hands to knead the ingredients together until you get a well-blended mixture. Make walnut-sized gnocchi from the mixture. Use your hands to insert a little of the filling and close the gnocchi well.
Melt the butter in a large pan and add the bread crumbs, a pinch of sugar and a sprinkling of cinnamon. Fry briefly.
In a large saucepan, bring to the boil plenty of salted water. Boil a few gnocchi at a time. Drain, toss them in the pan with the sauce and serve immediately.