Feathery, melt-in-the-mouth potato dumplings made from floury baked potatoes and 00 flour, gently poached and dressed with foaming browned butter, crispy fresh sage leaves, and Parmigiano Reggiano.
Bake the whole, unpeeled potatoes on a layer of coarse salt at 200°C for 50-60 minutes until completely tender. While still piping hot, peel the skins using a clean kitchen towel and pass the steaming potato flesh through a fine potato ricer directly onto a clean worktop. Allow steam to escape for 5 minutes.
Sprinkle the flour, salt, and nutmeg over the warm riced potato, then drop the egg yolk in the centre. Gently bring the dough together with a bench scraper until just cohesive without overworking. Roll into 2cm ropes, slice into 2cm pillows, and roll each piece gently over a ridged gnocchi board or fork tine.
Melt the butter in a wide frying pan over medium heat. When it begins to foam and sizzle, add the whole sage leaves. Cook for 2-3 minutes until the milk solids turn nutty amber-brown and the sage leaves become crisp and fragrant. Remove from heat immediately.
Drop the gnocchi in batches into a large pot of gently boiling salted water. Once they float to the surface, poach for 60 seconds, then scoop out with a slotted spoon directly into the warm sage butter. Toss gently to coat and serve immediately with grated Parmigiano Reggiano.