Preheat your oven to 425°F.

Use a fork to poke holes all over the potatoes. Place them on a baking sheet and bake for 45 to 60 minutes, until tender when pierced with a fork.

Let the potatoes cool just enough to handle, but keep them warm. Peel off and discard the skins.

Pass the potatoes through a ricer, or mash them with a fork in a large bowl until smooth and lump-free.

Transfer the potatoes to a lightly floured surface and shape them into a wide mound. Drizzle the beaten egg over the top, sprinkle with the salt, and add about one-third of the flour.

Use your hands or a bench scraper to gently lift and fold the potatoes into themselves to incorporate the flour and egg.

Add another third of the flour and repeat, folding and lightly kneading just until incorporated. Continue adding flour a little at a time until the dough is soft and pillowy but not sticky. You may not need all the flour, or you may need a bit more. Knead as little as possible.

Form the dough into a ball and cut it into 8 equal pieces. Lightly flour your hands and surface. Roll each piece into a rope about 1 inch thick, then cut into ¾-inch pieces.

Bring a large pot of well-salted water to a boil. Cook the gnocchi in batches, adding about one-third at a time.

Boil for about 2 minutes, or until the gnocchi float to the surface. Use a slotted spoon to transfer them to a colander set over a bowl.

Repeat with the remaining gnocchi and serve with your favorite sauce.