By J. KENJI LÓPEZ-ALT

A master class from J. Kenji Lopez on how to make the best roasted potatoes ever!

WHY IT WORKS

• Parboiling the potatoes with a hint of vinegar builds strong pectin bonds and a starchy outer layer of potato. 
• Tossing the parboiled potatoes in a bowl with a metal spoon creates microscopic nooks and crannies that make for an extra-crunchy exterior.
• Roasting in animal fat adds extra crispness and rich flavor.

So what is it that makes a potato crisp?

The potatoes above have been parboiled, then tossed roughly in a bowl with a metal spoon until their surfaces were roughed and scratched up. All those microscopic nooks and crannies will make for an extra-crunchy surface.

Potato Variety (Note)

You can use any type of potatoes you like for this, but there’s a tradeoff:

• Starchy russet potatoes will produce the crispest crust because of their high starch content, with fluffy, powdery interiors.
• Yukon gold potatoes (what I’ve used here) will produce crusts that are still very crisp, but not quite as crisp as that of a russet. They’ll also have interiors that are more creamy than fluffy. Some people like this contrast of textures. I’m on the fence, so I usually alternate between the two varieties.
• Red waxy potatoes will have the creamiest texture of all, but will lack a very strong, crisp crust. I don’t recommend them for this purpose.

Fat (Note)

Next question: What’s the best fat to use?

Well, if you can get your hands on it, this:

People often tout the awesomeness of duck fat with potatoes, and for good reason: It tastes awesome. Duck fat has a distinct richness and aroma that get absorbed very easily into the surface of a spud. On top of that, it’s got plenty of saturated fat and a high smoke point, which makes it an ideal medium for crisping up fried or roasted foods. (In general, the higher the saturated fat content of an oil, the more efficiently it’ll crisp foods.) Can’t get duck fat? Well, turkey fat or chicken fat collected from roasted birds will do just fine.

Bacon fat and rendered lard are also fine choices, as is just about any sort of animal-derived fat.

If you must use it, extra-virgin olive oil will certainly do admirably well, though you won’t get quite the same level of crispness you’d get out of an animal fat.

Once your potatoes are tossed in fat and seasoned well, all you’ve got to do is roast them in an extremely hot oven until they crisp up.

I roast mine directly on a heavy rimmed baking sheet—they have a tendency to stick to foil. The key is to make sure you let the underside crisp up completely before you even attempt to lift or flip them. If the potatoes don’t come off relatively easily, you run the risk of breaking off the tops, leaving the crisp bottom cemented to the bottom of the pan. This is not an ideal situation.

Moral: Your potatoes will release themselves from the pan when they’re good and ready. Don’t force them.

Ingredients:

4 1/2 pounds (2 kg) russet potatoes (see note), rinsed, peeled if desired, and cut into 2-inch chunks

Kosher salt

1 tablespoon (15 ml) white vinegar

1/4 cup (60 ml) duck fat (see note)

Freshly ground black pepper

12 sprigs thyme

Directions:

Adjust oven racks to lower and upper positions and preheat oven to 500°F (260°C). Place potatoes in a large saucepot and cover with cold water by 1 inch. Add 2 tablespoons (28g) salt and vinegar. Bring to a boil over high heat, reduce to a simmer, and cook until exteriors are tender, about 5 minutes. Potatoes should show slight resistance when poked with a paring knife or a cake tester. Drain potatoes and transfer to a large bowl.

Add fat to bowl with potatoes. Season with pepper and more salt to taste, then toss with a large metal spoon until exteriors are slightly bashed up and coated in a thin layer of potato/fat paste. Divide potatoes evenly between 2 heavy rimmed baking sheets. Spread thyme sprigs over potatoes.

Transfer baking sheets to oven and roast until bottoms of potatoes are crisp and golden brown, about 20 minutes total, swapping trays top for bottom and rotating them once halfway through roasting. Using a thin metal spatula, flip potatoes and roast until second side is golden brown, another 15 to 20 minutes. Discard thyme sprigs and serve.

Enjoy!!!!