From Andrew Carmellini's book Urban Italian
The Best Gnocchi
Timing: The potatoes take 1 hour or so, but once that's done, it's pretty quick--about ½ hour.
For the gnocchi you will need:
For the sauce you will need:
To prepare the gnocchi:
2. Prick each potato several times with a fork; place them 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 1 hour.
3. Remove the potatoes from the oven and let them cool just enough so that you can handle them, about 6 to 10 minutes. They should still be steaming when you cut them open. (If you let the potatoes get too cool, the proteins in the egg won't bind with the potatoes, and your gnocchi will fall apart, or you'll have to add too much flour and you'll end up with chewy potato bullets.)
4. Cut each potato in half lengthwise and scoop out the flesh with a spoon. Discard the skins. Pass the potato flesh through a food mill or press through a ricer set over a medium bowl.
5. Using your hands, gently stir the beaten egg, Parmigiano-Reggiano, olive oil, melted butter, salt, pepper, and 1 cup of the flour in with the potato. Stir only enough to combine: 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). The dough should feel soft and slightly tacky but not sticky — sort of warm and sexy.
6. Turn the dough out onto a lightly floured work surface. Working quickly, cut the ball of dough into inch-thick slices, using a dough cutter if you've got one, or a regular butter knife if you don't.
7. Roll each slice between your hands to form a ball.
8. Using the palms of your hands, roll each ball back and forth on your work surface until it extends into a long "snake," 14 to 16 inches long and about ¾ inch thick. (This isn't a precise measurement. You can make your gnocchi whatever size you want — this is just how I like 'em.) Keep adding more flour to the work surface as you go to help as you roll the dough.
9. Cut each snake in half and roll it out again, thinner, to the same length. Sprinkle the rolled-out snakes with flour to keep them from sticking.
10. Cut each snake into gnocchi-sized pieces (I like mine to be about 1 inch long), 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.
To cook the gnocchi:
1. Bring a large pot of salted water to a rolling boil.
2. Add the gnocchi all at once. Stir around once gently, so that the water is aerated and the dough doesn't become glued together like one big gnoccho.
3. Let the gnocchi cook until they bob to the surface (about 1 to 2 minutes); wait 1 more minute and then, using a slotted spoon or spider, remove the gnocchi. (Don't dump the gnocchi out into a colander the way you would spaghetti. All the gnocchi will crash onto each other and break.)
To prepare the sauce and finish the dish:
2. Remove the tomato sauce from the heat. Put the gnocchi right into the sauce when you remove them from the boiling water.
3. Toss the gnocchi in the sauce so every piece is thoroughly coated. Add the olive oil, butter, Parmigiano-Reggiano, and basil and mix well. Serve as quickly as possible.