Place whole, unpeeled potatoes in a pot of water and bring to a boil. Cook until fork tender, about 25–30 minutes, then drain.

Spread the flour onto a clean work surface.

While the potatoes are still warm, pass them through a potato ricer directly over the flour.

Drizzle the lightly beaten egg over the potatoes and add a pinch of salt.

Gently combine everything until a soft, smooth dough forms. Be careful not to overwork the dough — it should be pliable but not sticky.

Divide the dough into portions.

Roll each piece into a rope about ¾ inch thick, then cut into pieces about ¾–1 inch long.

Using your thumb, roll each piece over a rigagnocchi board or the back of a fork to create ridges.

Lightly sprinkle with semolina flour and arrange in a single layer on a tray until ready to cook.