Place the potatoes (with their skin) into large pot filled with cold water, bring to boil, and then add salt and cook for about 40 minutes. Peel the potatoes, puree them with a potato masher while they’re still hot and knead into dough with flour, egg and a pinch of salt.
Form 2 cm thick cylinders from the dough, cut them into pieces, press a little and place one grape onto each pillow, roll and shape into gnocchi.
Cook gnocchi in salted boiling water until they come up the surface. Melt butter. Pour it over gnocchi, add pepper and grated cheese. Decorate with fresh chives.