I am passionate about sweet potato fries. Possibly, I qualify as being clinically obsessed with them. I can’t think of a single food I crave more consistently than the salty sweet perfection that is sweet potato fries.
If I go out to dinner and sweet potato fries are on the menu, I order them. It doesn’t matter if it goes with the entrée I’ve chosen, they’re mine. While normally I will eat a sweet potato any which way, when I’m eating sweet potato fries, I’m picky about them. They have to suit MY idea of what a perfect sweet potato fry is: ALL-CAPS LEVEL CRISPY with no added sweetener because WHY in heaven’s name would you add SUGAR or somesuch to a SWEET POTATO? Seriously, people. I can sniff out sugar added to a sweet potato fry and it makes me cranky.
To me, the beauty of the sweet potato fry comes not in amplifying the already sweet tuber, but in playing off of it with salty and spicy. And friends, don’t even get me started on the disappointment that is a soggy sweet potato fry. Ugh. It’s like deflating a balloon of happiness with a wet noodle… Torturous.
That usually ends up being the problem with homemade sweet potato fries. Sweet potatoes are a little trickier to get super crispy than the good old regular potato. While I’m not one to shy away from deep-frying, I wanted to make crispy baked sweet potato fries. Because there were so many brands of tasty bakeable sweet potato fries in the freezer section, it seemed like it had to be possible to make them from scratch. I examined the backs of the bags of the brands I liked, used my previous experience as a professional slinger-of-pub-grub, made more than fifteen batches of sweet potato fries of varying degrees of success, but finally dialed in on a recipe that I’m confident will turn out crispy sweet potato fries every time! They’re so irresistible that even my no-vegetable trio gobbles these up enthusiastically!
I’m about to dazzle you with a breathtaking display of absolutely insane nit-picking detail on how to guarantee yourself crispy baked sweet potato fries. *Cue the theme music from ‘The Anal-Retentive Chef”.
How to Make Perfect Crispy Oven Baked Sweet Potato Fries
- Take your time cutting your sweet potatoes to size. By size, I mean 1/4-inch by 1/4-inch by whatever length matchstick pieces. Yes, you do need to be particular about cutting them to size. It’s better to err a little on the skinnier side than the fatter side if your knife work isn’t your strong point. The best way to accomplish this is to cut a little piece off of one side of the peeled sweet potato so it can sit more securely on the cutting board. Cut lengthwise into 1/4-inch thick ‘cards’. Then take each card and cut again into 1/4-inch thick matchsticks. I find it easier to do this -and far less frightening- by knife rather than by mandoline.
- SOAK YOUR SWEET POTATOES. I’m not joking. We soaked the regular potato fries in cold water in every restaurant where I worked. I applied the same technique to sweet potato fries and it worked beautifully. It draws the excess starch out of the sweet potatoes (or regular potatoes) which helps them cook through better to be crispy on the outside, tender on the inside without burning. Don’t skip this step or you’ll be disappointed.
- Line your sheet pans with heavy-duty foil (dull side up!) AND spritz them with non-stick cooking spray. I experimented with regular foil, heavy-duty foil, parchment paper, straight up nekkid pans, stoneware sheet pans, and silpat lined pans. Garden variety heavy-duty foil yielded my best results Don’t skip THIS step or you’ll be attempting to chisel sweet potato fries off of foil. If THAT doesn’t deter you from skipping this step, I don’t know what will.
- After draining, rinsing, and patting dry your soaked sweet potatoes, add two handfuls of them to a very large plastic bag along with 2 teaspoons of starch (*See Cook’s Notes) and shake vigorously. You should keep as much air in the bag as you can so the fries move around like popcorn in an air popper. The idea is to get a whisper thin coating of the starch on the potatoes, not to COVER them in starch. In fact, when you dump them out into a bowl, you should have to look pretty closely to even see the starch on them. Too much starch makes the fries taste like starch rather than sweet potatoes. Ick.
- DO NOT ADD SALT BEFORE COOKING. In this particular case, adding salt before cooking yields limp, sad fries. You can get them plenty salty after baking them.
- Let’s talk oil, shall we? Yes, I know we already spritzed the pans with non-stick cooking spray, but that’s an insurance policy… that’s not a crisping agent. Don’t even think about olive oil here. While it’s super tasty, the temperature and duration of the cooking process will make olive oil billow smoke out of your oven before the sweet potatoes are even close to being done. My favourite oil for the job is grapeseed, but if you cannot find it, canola or peanut should stand in well.
- Even if you fail to heed my super detailed advice anywhere else, DO NOT CROWD THE PAN. If I could type it a million times and not be obnoxious, I would. Science dictates that if you crowd a pan, your fries will automatically be soggy. How so? When you’re ‘crisping’ these, you’re releasing the moisture from them. You release the moisture by applying heat and allowing air to circulate in your oven. If you apply the heat but don’t allow the air to circulate around them, the moisture will have no where to go and will sit there steaming around those fries. You want steamed sweet potato fries? Neither do I. Keep them spaced out, not touching as much as possible, and absolutely, positively only in a single layer.
- By the same token, don’t crowd the oven. You don’t want too much moisture releasing from too many sweet potatoes at the same time or you’re essentially giving the pretty little things a nice sauna bath.
- Halfway through the baking time, you’ll remove the pans from the oven to flip the fries. This is best accomplished by using a thin metal spatula or fish turner. It will have enough backbone to get under the fries and enough flexibility not to mangle them. When you flip them, be sure they land in a single layer not touching. You can adjust them with tongs if needed.
- Oh, and when you return the pans to the oven, rotate ’em from top to bottom AND front to back. The pan that started in the top part of the oven should end the cooking process in the bottom of the oven facing the opposite direction from which it started. This helps compensate for any hotspots your oven may have.
- Ready for something counter-intuitive? When your fries are done, prop the oven door open about halfway and let them cool on the pan for at least 10 minutes. Believe or not, unlike regular potato fries, these bad boys crisp up even more as they cool slightly.
Even with all this advice, you may find the first batch doesn’t work out exactly the way you planned.
- If your fries are darkening too quickly, but still not cooked through to your liking, you may have an oven that runs hot. Conversely, if you feel like you’re baking your fries FOREVER and they’re not crisping, your oven may run a little cool. Get a $5 oven thermometer from Walmart and pop it in there to see how accurate your oven’s calibration is then compensate for it.
- If your fries are soggy and you’ve followed all of my advice, you may have a smaller oven than the one I tested my fries in and may have to bake them one tray at a time.
- Sadly, there are some bum sweet potatoes out there. It may be that you got one that was past its prime.
- I didn’t mean to be vague when I said to toss the fries with starch, but I had a little explaining to do. In a perfect world, the best, crispiest baked sweet potato fries are made with a blend of three powdered starches: cornstarch, brown rice starch, and tapioca starch in a ratio of 2:1:1. It’s a lot easier to find the more unusual tapioca and rice starches now that gluten-free baking is more prolific, but if you can’t source them, have an allergy to one of them, or just don’t feel as compelled to get down and dirty with making the most perfect baked sweet potato fries ever, you can use all of one of the kinds. Cornstarch is the easiest to find, but health-food stores, well stocked grocers, and Amazon are great places to buy both tapioca starch and brown rice starch. If you are fortunate enough to be in possession of all three starches, whisk them together in a bowl or jar before adding to the fries.
- I like my sweet potato fries with a hint of spice. To get this, I add about 1/4 teaspoon (or more, depending on how sassy I’m feeling) of ground chipotle powder when tossing the fries with oil before cooking. This is, however, strictly optional. I’m convinced, though, that this is part of the reason that the three of my children who are vegetable-phobic love the fries.
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- 2 large sweet potatoes (about ¾ pound, give or take)
- 4 teaspoons starch (corn starch, tapioca starch/flour, brown rice starch/flour, or a mixture of any or all of them)
- 2 tablespoons grapeseed, peanut, or canola oil
- ¼-1/2 teaspoon chipotle powder
- non-stick cooking spray
- salt to taste
- Peel the sweet potatoes and cut them into ¼-inch by ¼-inch matchsticks. Put them in a bowl and cover with cold, fresh water. Let them soak for 1 hour or up to overnight. Pour the water and sweet potato matchsticks into a colander, rinse with fresh water, then pat dry with paper towels. They should not be visibly wet, but they don't have to be bone dry.
- Preheat oven to 425°F.
- Line two half-sheet pans with heavy-duty foil and spritz lightly with non-stick cooking spray. Set aside.
- Add half of the sweet potato matchsticks to a very large plastic bag. Sprinkle 2 teaspoons of the starch over the potatoes, cinch the top (trapping as much air in the bag as you can when you cinch it) and shake vigorously to coat the fries. Empty the bag into a mixing bowl and use your hands to toss with 1 tablespoon of the oil and the chipotle powder (if using). Arrange the fries on the prepared pan in a single layer, not touching. Repeat with the remaining fries, starch, and oil.
- Arrange the pans in the oven so that one is in the top third of the oven and the other is in the bottom third of the oven. Set the timer for 15 minutes. After 15 minutes, use a stiff metal spatula or fish turner to get under the fries and flip them over. Remember to keep them in a single layer after flipping. Return the pans to the oven, rotating the pans from top to bottom and front to back. In other words, the one that started in the top third of the oven should end in the bottom third of the oven facing the other direction. Bake for another 10-15 minutes, or until they have browned and are cooked clean though.
- Shut the oven off, prop the door open halfway, and let cool and crisp up further for 10 minutes before serving. Toss with salt to taste.
This post was originally published April 17, 2014.