How to make potato gnocchi

Wrong season.  I know.  If I was a cooking magazine, I would wait to publish this until fall.  But I am sure you'll forgive me, particularly if I give you a good recipe for potato (and sweet potato) gnocchi.

Why did I decide to make sweet potato gnocchi in April?  I needed a picture for a Gnocchi class that I have in the works and sweet potato gnocchi are probably the most photogenic of them all.

If you have been traumatized by a bad gnocchi making experiences, I just want to assure you that it's not you -- it's the recipe.  I don't know why there are so many recipes in existence that result in either slimy potato blobs disintegrating as you try to cook them or dense rubber balls?

Here is what you need to make feather light little pillows:

Scale
Without a scale, the odds of you getting the correct ratio of potatoes to flour are very slim.  My medium potato and your medium potato can be very different, and my cup of flour and your cup of flour can be very different too.  Can't you adjust based on how the dough feels?  No.  Adjusting means more kneading, which means more gluten development, which means more chew.  If you want rubber balls, go ahead and adjust.  If you want feather light pillows, get a scale.

Potato ricer or a food mill
Both of these tools will do the job of pureeing and fluffing up the potatoes, but they might not be found in every kitchen.  Don't use a food processor since it will compress the potatoes.  If you don't have either ricer or food mill, I would suggest getting a ricer -- it's easier to store and cheaper.

Use Boiling not Baking Potatoes
You need boiling potatoes (the ones that keep their shape after cooking).  If you use russets (baking potatoes), you'll end up with slimy disintegrating potato blobs.  Yukon gold produce the best possible gnocchi both in flavor and texture when I get them from the farmer's market in the fall.  Yukon gold potatoes from a regular store can be somewhat unpredictable and can result in gnocchi that don't hold their shape.  Red bliss potatoes produce the most reliable (if not absolutely heavenly) results and that's my choice of potato year round.

For the sweet potato version, I combine boiling potatoes (red bliss or yukon gold) with sweet potatoes in the ratio of 55% cooked and riced boiling potatoes to 45% cooked and riced sweet potatoes.  Buying sweet potatoes can be very confusing since many of them are sold as "yams."  For this recipe, I prefer Beauregard sweet potatoes (usually sold as "sweet potato") or Jewel yams.  Red Garnet will work in a pinch, but they are less sweet and more watery.

Potato gnocchi

Serves 6 as the first course

For the dough:
1.5 Lb (680g) red bliss or yukon gold potatoes
unbleached all-purpose flour (see the recipe for instructions on measurement)
Salt (see the recipe for instructions on measurement)

For shaping:
Semolina
Unbleached all-purpose flour

Dough

1. Fill a pot that can later hold a steamer insert with 3 inches of water. Set over high heat and bring the water to a boil. Put potatoes into the steamer insert, set over pot and cover. Reduce heat to medium and steam until potatoes are tender when pierced with a toothpick, 35-50 minutes.
2. Cool potatoes for 5 minutes, peel them while still hot.  Inspect potatoes and discard any parts that are black, gray or suspicious looking.  Put potatoes through a potato ricer or food mill and place in a large bowl.  Weigh them to see how much you got (make sure you tare the bowl before adding potatoes).  Cool potatoes to room temperature, 30-45 minutes (you can speed things up by placing them in the fridge and stirring every 10-15 minutes).
3. Divide the potato weight (the final weight after cooking and ricing) by 2.8.  That's your flour weight.  For example, if you had 600g of riced potatoes, you'd need 214g flour (600/2.8).
4. Divide the potato weight by 100 to get the salt weight.  For example, if you had 600g of riced potatoes, you'd need 6g of salt.  Salt is much easier to measure in grams than in fractions of ounces.
5.  Add the salt and the flour to potatoes. Toss with your hand to distribute flour evenly.  Gently knead the dough with your hand just until it comes together (don't over mix or the gnocchi will be tough). It should feel a little dry at first, but should come together into a rough and soft ball.  Flatten it into a thick disc.  Shape immediately.

Shaping

1. Line a large cookie sheet with parchment paper or foil, and sprinkle generously with semolina.
2. Dust the dough with all-purpose flour on both sides and place on a work surface.
3. Cut the dough into 2/3 inch thick slices (like slices of bread).  Cut each slice in half lengthwise to give you strips.  Roll each strip with the floured palms of your hands on a floured work surface into a 2/3 inch ropes (use all-purpose flour for this). Cut the ropes crosswise into 2/3 inch pillows using a pastry scraper (you can also use a knife on a cutting board).  Sprinkle the pillows with all-purpose flour and gently toss.  Place them on the cookie sheet. Don't let the gnocchi touch each other or they'll stick together. After shaping, you can keep the gnocchi at room temperature for several hours.  Don't cover the gnocchi, or they'll get soggy.  

Cooking

1. Bring a large pot of very generously salted water to a boil.
2. Warm up a large serving bowl in the oven at 200F.
3. Bring the cookie sheet with gnocchi close to the pot, lift the parchment paper and dump the gnocchi into the water. It's ok for semolina to get into the water. It will settle on the bottom of the pot and won't be present in the final dish. If the gnocchi got stuck to the parchment paper, dunk the whole parchment paper into the pot and gently shake them off into the water with a wooden spoon.  
4. As soon as the gnocchi are in the water, reach in under them with a slotted spoon to release them from the bottom of the pot.  
5. In 1-2 minutes, gnocchi should float.  Wait 30 seconds, and taste one.  If the center is too floury, cook another minute and taste again.  Spoon them out with a slotted spoon into the warm bowl. Dress with the sauce of your choice and serve immediately.

Sweet potato variation

Start with roughly equal weights of raw boiling and sweet potatoes.  For 6 first course portions, you'll need roughly 3/4 Lb boiling and 3/4 Lb sweet.  Steam them both until tender.  Weigh the boiling potatoes after cooking, peeling and ricing.  Divide that number by 1.2 and only use this amount of riced sweet potatoes (use the rest for another application).  When ricing sweet potatoes, make sure all the fibers stay in the ricer and don't end up in the final dish.

For example, if you have 330g riced boiling potatoes, you'll need 275g sweet potatoes.  That's 605g total.  Let's round it to 600g to make math a little easier.  Divide that by 2.8 to get your flour weight (214g) and divide by 100 to get your salt weight (6g).

You can add a few gratings of nutmeg and a few pinches of cinnamon to the sweet potato dough.