The Best Gnocchi

INGREDIENTS

4 large Idaho potatoes (about 2 lbs.), scrubbed
1 whole egg, beaten
1½ cups all-purpose flour
2 tablespoons grated Parmesano-Reggiano
1 tablespoon extra-virgin olive oil
1 tablespoon unsalted butter, melted
1 teaspoon salt
¼ teaspoon coarse ground black pepper

INSTRUCTIONS
Center a rack in the oven and preheat to 425°F. Prick each potato several times with a fork and place on a baking sheet or in a roasting pan large enough to hold them all in a single layer. Bake in the oven until the potatoes are tender enough to be easily pierced with a small knife (about 60 minutes).
Remove the potatoes from the oven and let them cool slightly – just enough so that you can handle them, not more (about 6 to 10 minutes). They should still be steaming when you cut them open. If you let the potatoes get too cold, the proteins in the egg won’t bind with the potatoes, and your gnocchi will fall apart. Cut each potato in half lengthwise and scoop out the flesh with a spoon. Pass the potato flesh through a food mill or press through a ricer set over a medium bowl. When it comes through the ricer, the potato should look sort of like Play-Doh.
Using a wooden spoon, gently stir in the beaten egg, Parmesan cheese, olive oil, melted butter, salt, and pepper, and 1 cup of flour, reserving the rest. The mixture should be stirred only until the ingredients are combined; anything more will overwork the dough, and your gnocchi will come out tough (like the frozen-in-a-bag variety). Work the mixture into a smooth ball; if the dough seems a little too moist for this, add a touch of flour (the moisture level in every potato is different, so every batch of gnocchi will be a bit different, too).
Turn the dough out onto a lightly floured work surface. Working quickly, cut the dough into inch-wide slices, using a dough cutter if you’ve got one, a regular dinner-table knife if you don’t. Roll these between your hands to make them into a ball. The dough should feel soft, slightly tacky but not sticky. Roll out each piece into long logs, approximately 14” to 16” long, about ¾“ thick. Cut each one in half and roll it out again, thinner, to the same length. Sprinkle the rolled-out logs with flour to keep them from sticking, and keep adding more flour to the work surface as you go to help as you roll the dough. Cut each log into gnocchi-sized pieces (about 1 inch by 1 inch), and place the pieces on a lightly floured baking sheet. Cover this with a cloth or plastic wrap until you’re ready to cook the gnocchi, so they don’t dry out.
Bring a large pot of salted water to a rolling boil. Add the gnocchi all at once (or as close to it as possible). Stir once gently all around, so that the water is aerated and the dough doesn’t become glued together. Let the gnocchi cook until they rise to the surface (about 1-2 minutes); wait one more minute and then, using a slotted spoon or a spider, remove the gnocchi. Don’t ever dump the gnocchi out into a colander the way you would spaghetti: that’s a disaster. All the gnocchi crash onto each other and break.