The Best Roasted Sweet Potatoes
Tender, caramelized roasted sweet potatoes glazed with olive oil, fresh parsley, and a hint of honey—simple, flavorful, and perfectly sweet without relying on excess sugar.
Sweet Potatoes 101
In the U.S., what we call “yams” are actually a type of sweet potato. True yams are large, starchy roots native to Africa, rarely found in American grocery stores. Sweet potatoes fall into two main categories:
– Dry varieties (like white-fleshed American or Okinawan purple sweet potatoes): Starchier, less sweet, and fluff up when cooked—great as a potato substitute.
– Moist varieties (such as Garnet or Ruby, often labeled “yams”): Higher in water and sugar, cooking up creamy and rich. These are the stars of this recipe.
Converting Starch Into Sugar
Starch is a complex molecule made of glucose, but our tongues don’t recognize it as sweet until it breaks down into simpler sugars like maltose (two glucose molecules). Sweet potatoes are packed with starch, and the key to maximizing their sweetness is activating enzymes that break down this starch into maltose.
This enzyme action occurs in a specific temperature range: it starts when starch granules absorb moisture and expand around 135°F (57°C) and stops when heat denatures the enzyme around 170°F (77°C). The longer a sweet potato stays in this zone, the more maltose forms—resulting in deeper, natural sweetness.
Why Par-Cooking Works
To leverage this enzyme activity, par-cooking sweet potatoes in water between 135–170°F (57–77°C) before roasting is game-changing. We tested three batches: one roasted directly at 350°F, one par-cooked at 150°F for an hour before roasting, and one par-cooked overnight. The par-cooked potatoes browned faster (thanks to higher sugar content) and tasted significantly sweeter and more flavorful than the straight-roasted batch. Surprisingly, the one-hour par-cook was nearly as good as the overnight version—proving an hour is all you need for maximum sweetness.
How to Par-Cook Sweet Potatoes
If you have a sous vide device, bag the potatoes and cook at 150°F (any higher and they soften too much before roasting), then roast later. For those without sous vide, try a beer cooler: seal potatoes in a zipper-lock bag, submerge in 150°F water in a cooler, close, and wait an hour.
The easiest method? Bring 3 quarts of water to a boil, add 1 quart of room-temperature water (cooling it to around 175°F), then add sliced potatoes. The potatoes will lower the temperature to the ideal range. Cover the pot, set it in a warm spot for a couple hours, and you’re ready to roast. No fancy equipment needed—just patience.
Recipe Details
The Best Roasted Sweet Potatoes
Prep Time: 5 minutesCook Time: 55 minutesActive Time: 20 minutesResting Time: 60 minutesTotal Time: 2 hoursServes: 6–8
Ingredients
3 pounds (1.4 kg) sweet potatoes (peeled or skin-on), quartered and sliced into ½-inch pieces
6 tablespoons (90 ml) extra-virgin olive oil, divided
Kosher salt and freshly ground black pepper, to taste
2 tablespoons chopped fresh parsley
1 tablespoon (15 ml) honey, maple syrup, or agave nectar
Directions
Par-Cook the Potatoes: Place sweet potatoes in a large saucepan and cover with water. Heat to 160°F (71°C) (use an instant-read thermometer to check). Cover and let sit for 1 hour.
Prep the Oven: While the potatoes rest, adjust oven racks to the upper and lower middle positions and preheat to 400°F (200°C).
Roast the Potatoes: Drain the potatoes and toss with 3 tablespoons of olive oil, salt, and pepper. Spread evenly on two rimmed baking sheets. Roast for 30 minutes until the bottom is browned, then flip with a thin spatula and roast 20 minutes more until tender and browned on both sides.
Finish and Serve: Transfer potatoes to a large bowl. Toss with the remaining 3 tablespoons of olive oil, parsley, and honey (or sweetener of choice). Serve immediately.
Special Equipment
2 rimmed baking sheets
Instant-read thermometer
Nutrition Facts (per serving)
251
Calories
10g
Fat
37g
Carbs
3g
Protein
