Prep: 3 hours
Total: 3 1/2 hours
2 pounds large orange-fleshed sweet potatoes
1 teaspoon baking soda
1 cup plus 2 tablespoons cornstarch
Peanut oil, for frying
1 cup club soda or water
Kosher or fine sea salt
1. Line a baking sheet with parchment paper and make enough room in the freezer for said baking sheet.
2. Peel the sweet potatoes, if desired, and cut them lengthwise into 1/4-inch-thick batons (fry shapes). Place them in a bowl with the baking soda and 2 tablespoons cornstarch, and toss. Arrange the sweet potatoes on the baking sheet in a single layer, making sure they are not touching. Freeze them until rock hard, at least 3 hours. If making fries later, transfer to a gallon-size zip-top freezer bag; they will keep frozen for up to 2 weeks.
3. Pour the oil into a large, heavy pot, preferably a Dutch oven, that's fitted with a deep-fry thermometer to a depth of 2 inches. Set the pot over medium heat and begin gently warming the oil to 375ºF.
4. In a large bowl, whisk together the remaining 1 cup cornstarch and the club soda. Stack several layers of brown paper on a baking sheet.
5. When the oil reaches 375ºF, drop a handful of sweet potatoes into the cornstarch mixture and coat evenly. Lift them from the bowl, letting any excess drip into the bowl, and carefully add them to the oil. Fry, stirring with a spider so they do not stick to the bottom of the pot, until deep golden brown and cooked through, about 8 minutes. Using the spider, transfer the fries to the brown paper to drain. Immediately season with salt. Repeat with the remaining sweet potatoes, returning the oil to 375ºF between batches.
AUTHOR'S NOTE: This recipe was reprinted with permission of the author from the book, Sweet Potatoes: Roasted, Loaded, Fried, and Made into Pie.