Why This Recipe Works
- Par-cooking the potatoes in 160°F (70°C) water enhances the development of simple sugars, leading to sweeter and more flavorful roast potatoes.
- Roasting the potatoes on aluminum baking sheets conducts more heat, browning and crisping them better and faster.
We all face the same question each year as Thanksgiving approaches: Do we stick with the classics or do something a little different? And, if we do something different, just how different do we want to get? I came up with a few twists on the classic sweet potato. Here’s a riff on the traditional, but you can also try this savory miso-scallion version or a spicy, smoky sweet potato dish.
In each case, I stick with a technique Kenji has written about before, which calls for par-cooking the potatoes in 160°F (70°C) water. This temperature helps maximize the transformation of complex starches into simple sugars. Above 170°F (77°C), the enzymes that do the heavy lifting shut down, leading to less sweet and flavorful potatoes. Then the potatoes are tossed in oil and roasted until they're nicely browned and slightly crisp in spots.
These potatoes are bathed in a rich and buttery sauce that's been infused with rosemary and a base note of savory chicken stock. I make it by melting the butter in a saucepan, then cooking it until the milk solids turn a deep hazelnut color. As soon as it reaches that brown shade, I remove it from the heat and throw in sprigs of fresh rosemary. They'll sizzle and fry in the hot butter, releasing their woodsy-piney aroma into it (and into your kitchen—it smells great).
I don't stop there, though. After that, I pour in a small amount of chicken stock that I've spiked with unflavored gelatin. The gelatin adds a rich viscosity to the stock (especially important if your stock isn't homemade), which ensures that the sauce doesn't end up with a thin, watery texture.
I return it to the heat at this point and simmer it until the stock is further reduced and syrupy, with a deep, meaty flavor. Then I fish out and discard the rosemary sprigs. To balance out all that richness, I hit it with a splash of fresh lemon juice, plus plenty of salt so the flavor really pops.
When the potatoes are ready, I just toss them with the sauce, and I'm done.
Brown Butter Rosemary Roasted Sweet Potatoes Recipe
Browned, rosemary-infused butter is enriched with reduced chicken stock and tossed with roasted, caramelized sweet potatoes.
3 pounds (1.4kg) sweet potatoes, peeled and cut into 1/2-inch chunks
3 tablespoons (45ml) vegetable or canola oil
Kosher salt and freshly ground black pepper
1/2 packet unflavored gelatin (about 1 1/4 teaspoons; 4g)
1/4 cup (60ml) homemade or store-bought low-sodium chicken stock
1 stick unsalted butter (8 tablespoons; 115g)
3 rosemary sprigs
1 teaspoon (5ml) fresh juice from 1 lemon
Place sweet potatoes in a large saucepan and cover with cold water. Heat water to 160°F (70°C) as registered on an instant-read thermometer. Cover and set aside for 1 hour.
Adjust oven racks to upper-middle and lower-middle positions and preheat oven to 400°F (200°C). Drain sweet potatoes and transfer to a large bowl. Toss with oil and season to taste with salt and pepper. Spread sweet potatoes on 2 rimmed baking sheets and roast until bottom sides are browned, about 30 minutes. Carefully flip potatoes with a thin spatula and roast until second side is browned and potatoes are tender, about 20 minutes longer.
Meanwhile, in a small container, sprinkle gelatin over chicken stock and let bloom for 5 minutes. Microwave until gelatin is dissolved, stopping and stirring as needed to help it dissolve, about 2 minutes.
In a small saucepan, melt butter over medium-high heat until foamy. Continue to cook, swirling pan, until milk solids in butter turn a deep hazelnut brown, 1 to 2 minutes. Remove from heat and add rosemary (don't be alarmed; butter will foam and fizzle when rosemary is added), swirling to coat.
Add chicken stock to butter, return to medium heat, and bring to a simmer. Cook, swirling, until stock reduces slightly and sauce becomes rich and silky, about 3 minutes. Remove from heat, discard rosemary, and add lemon juice. Season with salt.
In a mixing bowl, toss potatoes with butter sauce and serve. Potatoes can be made in advance, tossed with sauce, and set aside until ready to serve; rewarm in the oven before serving.
Aluminum rimmed baking sheets, instant-read thermometer
|Nutrition Facts (per serving)|
|Servings: 6 to 8|
|Amount per serving|
|% Daily Value*|
|Total Fat 17g||22%|
|Saturated Fat 8g||38%|
|Total Carbohydrate 35g||13%|
|Dietary Fiber 6g||20%|
|Total Sugars 11g|
|Vitamin C 34mg||169%|
|*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.|