From Cook’s Illustrated’s Cook’s Science
- ½ cup cornstarch
- Kosher salt
- 1 teaspoon baking soda
- 3 pounds sweet potatoes, peeled and cut into 3/4-inch-thick wedges, wedges cut in half crosswise
- 3 cups peanut oil
- good sea salt, like Maldon or Fleur de Sel, for sprinkling at the end
- Adjust oven rack to middle position and heat oven to 200 degrees. Set wire rack in rimmed baking sheet. Whisk cornstarch and 1/2 cup cold water together in large bowl.
- Bring 2 quarts water, 1/4 cup salt, and baking soda to boil in Dutch oven. Add potatoes and return to boil. Reduce heat to simmer and cook until exteriors turn slightly mushy (centers will remain firm), 3 to 5 minutes. Whisk cornstarch slurry to recombine. Using wire skimmer or slotted spoon, transfer potatoes to bowl with slurry.
- Using rubber spatula, fold potatoes with slurry until slurry turns light orange, thickens to paste, and clings to potatoes.
- Heat oil in 12-inch nonstick skillet over high heat to 325 degrees. Using tongs, carefully add one third of potatoes to oil, making sure that potatoes aren’t touching one another. Fry until crispy and lightly browned, 7 to 10 minutes, using tongs to flip potatoes halfway through frying (adjust heat as necessary to maintain oil temperature between 280 and 300 degrees). Using wire skimmer or slotted spoon, transfer fries to prepared wire rack (fries that stick together can be separated with tongs or forks). Season with sea salt to taste and transfer to oven to keep warm. Return oil to 325 degrees and repeat in 2 more batches with remaining potatoes. Serve immediately.
NOTES FROM AMERICA’S TEST KITCHEN:
If your sweet potatoes are shorter than 4 inches in length, do not cut the wedges crosswise. They prefer peanut oil for frying, but vegetable oil may be used instead. Leftover frying oil may be saved for further use; strain the cooled oil into an airtight container and store it in a cool, dark place for up to one month or in the freezer for up to two months.
Serve with fry sauce if you wish: Stir together 6 tablespoon mayonnaise, 1 tablespoon Asian chili-garlic sauce, and 2 teaspoons vinegar. This is delicious, but totally optional—the fries are so good on their own.
BLANCH:Blanching the wedges helps ensure that their interiors fully cook and turn creamy when fried. Adding baking soda to the water makes them tacky on the outside.
COAT:The cornstarch slurry stays put thanks in part to the parcooked wedges’ tacky exteriors, and it crisps up beautifully in the hot oil.
FRY:Frying the wedges in a nonstick skillet prevents them from sticking to the bottom of the pan. The shallow vessel also makes using far less oil possible.
- Prep Time: 20 minutes
- Cook Time: 20 minutes
- Category: Side Dish
- Method: Deep Fried
- Cuisine: American
Keywords: homemade, sweet, potato, fries, deep, fried, thick, cut