how to make sweet potato fries

We love the addictive dinner staple that is sweet potato fries – if for no other reason than for adding a little orange to our otherwise green dominated plate. Did you know that it’s best to consume green and orange veggies together for optimal liver health? 

So – you’re as hooked on sweet potato fries as we are? It could be that you’re skipping the essential step that only hard-core foodies may have mastered. Author Mary-Frances Heck calls the secret step “the hard way” to make sweet potato fries in her cookbook devoted to the most loved root veggie of the 21st century. Here’s what you need to know…

Making really good sweet potato fries is one of the great recipe challenges of the twenty-first century because whether roasted or deep fried, a few minutes later they’re limp. Sweet potatoes are considered healthier than white potatoes because they contain less simple starch (which is metabolized as sugar) — and this is the root of why sweet potato fries don’t crisp on the outside while staying fluffy on the inside.

French fried white potatoes are first cooked at a low temperature. This cooks the potato and gels the outer layer of starch on its surface. Then they are cooked again at a higher temperature to crisp the gelled starch. The result is a crisp, dry outside encasing moist potato inside. Processed food companies, chefs and even NASA conducted test after test to approximate this gelled starch coating for sweet potatoes. Experimental steps include washing, drying, blanching, alkalinizing, dehydrating, freezing, dredging and battering the poor spuds before their eventual trip(s) through hot oil. Thus the following two recipes evolved after testing a dozen methods and studying the results.

The Easy Way Making sweet potato fries The Easy Way distills the oven-fry method to its most essential steps: cutting uniformly so they cook evenly, oiling and seasoning aggressively, then roasting in a hot oven until crisp.

The Hard Way Sweet potato fries made The Hard Way are deep fried and require a few steps that will dirty some dishes, but are well worth it. First, a dusting of baking soda and cornstarch clings to the fries and begins to rough up and gelatinize the surface starch. Freezing them buys the outside of the fries more time to crisp in the oil before the inside becomes soft. Dipping the frozen fries in a slurry adds a layer of dissolved starch that begins to gel as soon as it hits the oil. These essential steps yield sweet potatoes worthy of the term fry.

on seasonings While both recipes only call for salt, try adding a teaspoon or two of any of your favorite seasonings. Got some herbes de Provence? Toss ’em in there. Spanish paprika? Definitely. Za’atar, curry powder, Mrs. Dash, Old Bay or Tony Chachere’s? Yes, please.

Sweet Potato Fries, The Easy Way
Serves 4


2 pounds orange-fleshed sweet potatoes
2 Tbsp olive oil or melted unsalted butter
1½ tsp kosher or fine sea salt


Preheat the oven to 375°F. Line a rimmed baking sheet with parchment paper.

Peel the sweet potatoes (if desired). Cut into slabs, batons, wedges, coins, half-moons or cubes. They can be any size as long as they are not less than ¼ inch and not more than 1 inch thick.

Place in a large bowl and drizzle with oil. Season with salt and choice of spices (if using) and toss to coat. (Use about 1½ tsp salt if not using additional seasoning. Adjust salt content depending on preferred spice mix.)

Dump sweet potatoes onto prepared baking sheet, scraping any seasoning or fat clinging to the bowl and arrange in a single layer. Roast (turn once if bottoms darken quickly) until tender and browned, about 15 to 25 minutes depending on size.

Sweet Potato Fries, The Hard Way
Serves 4


2 pounds large orange-fleshed sweet potatoes
1 tsp baking soda
1 cup plus 2 Tbsp cornstarch
peanut oil for frying
1 cup club soda or water
kosher or fine sea salt


Line a baking sheet with parchment paper and make enough room in the freezer for said baking sheet.

Peel sweet potatoes, if desired, and cut them lengthwise into ¼-inch-thick batons (fry shapes). Place in a bowl with baking soda and 2 Tbsp cornstarch, toss. Arrange sweet potatoes on baking sheet in a single layer and make sure they are not touching. Freeze 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.)

Pour oil into a large, heavy pot (preferably a Dutch oven) fitted with a deep-fry thermometer to a depth of 2 inches. Set pot over medium heat and begin gently warming oil to 375°F.

In a large bowl, whisk together remaining 1 cup cornstarch and club soda. Stack several layers of brown paper on baking sheet.

When the oil reaches 375°F, drop handful of sweet potatoes into cornstarch mixture and coat evenly. Lift from bowl, letting excess drip into bowl and carefully add to oil. Fry (stir with a spider utensil so fries do not stick to bottom of pot) until deep golden brown and cooked through, about 8 minutes.

Using the spider, transfer fries to brown paper to drain. Immediately season with salt. Repeat with remaining sweet potatoes, returning the oil to 375° between batches.

Recipes and photographs reprinted from Sweet Potatoes: Roasted, Loaded, Fried, and Made Into Pie. Copyright © 2017 by Mary-Frances Heck. Photographs copyright © 2017 by Kristin Teig. Published by Clarkson Potter/Publishers, an imprint of Penguin Random House LLC.

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