Why It Works
- Roasting the sweet potatoes first at a low temperature enhances their sweetness, then a few minutes at a higher temperature browns them gently.
- A splash of fresh orange juice and zest adds depth and fragrance without being cloying.
After Thanksgiving, the big question is what to do with the leftovers. As someone who works on recipes each day, I have a different challenge: what to do with the leftover raw ingredients that I didn't end up using in any dishes at all.
This year it was a big bag of sweet potatoes still sitting on my counter after everything else was done. Personally, after a lot of holiday cooking, I'm in the mood for easy, soothing foods—big projects can wait a week or two while I catch my breath. Easy and soothing, for me, often means soup.
And so it was for those sweet potatoes. I started by using Kenji's low-temperature oven method to roast the sweet potatoes: sweet potatoes convert their starch to sugar best at gentle heat. Crank it too high and you'll halt their sweetening prematurely. Only after an hour at the low heat did I increase the oven temperature to help brown them a little and deepen their flavor.
While the potatoes cooked, I sweated onion, garlic, and carrot in a soup pot, then added the potatoes. I topped it off with some chicken stock (though homemade vegetable stock works just as well for those hoping to keep things vegetarian) and blended it to a smooth purée. A small splash of orange juice added some subtle extra flavor. The basic technique is outlined in this primer on creamy soups.
I decided to go above and beyond by passing my soup through a fine-mesh strainer. It produces a significantly better texture, but I can't lie: It's a minor pain to do. Skip it or do it, as you prefer.
Then, for a garnish, I made a riff on gremolata by crushing pistachios, then stirring in orange zest (from the same orange I had juiced), scallions, mint, and olive oil.
Just like that, my problem was solved.
4 pounds sweet potato, peeled and cut into 1/2-inch dice
6 tablespoons vegetable, canola, or grapeseed oil, divided
4 medium carrots, peeled and diced
1 medium onion, chopped
5 cloves garlic, crushed
2 sprigs sage (optional)
1/4 cup fresh juice and 1 tablespoon freshly grated zest from 1 medium orange, divided
3/4 cup shelled roasted pistachios, crushed in a mortar and pestle or food processor
2 scallions, thinly sliced, white and light green parts only
2 tablespoons very thinly sliced fresh mint leaves (from about 5 sprigs)
Pinch cayenne pepper
1/2 cup extra-virgin olive oil
Preheat oven to 300°F (150°F). Toss sweet potato with 4 tablespoons vegetable oil and salt. Spread sweet potato on 2 rimmed baking sheets and bake for 1 hour, rotating pans front to back and top to bottom halfway through cooking. Increase oven temperature to 375°F (190°C) and cook until sweet potatoes are tender and lightly browned around the edges, about 25 minutes.
In a large pot, heat remaining 2 tablespoons vegetable oil over medium-high heat until shimmering. Add carrot, onion, garlic, sage (if using), and a generous pinch of salt and cook, stirring, until vegetables are just tender.
Add sweet potatoes and stock and bring to a simmer. Cook for 10 minutes until vegetables are very tender. Discard sage, if using. Add orange juice. Using an immersion blender or countertop blender, blend soup until smooth. Season with salt.
If desired, pass soup through a fine-mesh strainer using a rubber spatula to plunge and scrape it through (it may not seem like it at first, but almost all of the soup will pass through).
In a mixing bowl, stir together pistachios, orange zest, scallions, mint, and cayenne pepper. Fold in olive oil and season with salt.
Serve soup, spooning pistachio salsa on top.
If you choose to strain the soup through a fine-mesh strainer, thin soup to desired consistency with extra stock or water if necessary.
|Nutrition Facts (per serving)|
|Servings: 4 to 6|
|Amount per serving|
|% Daily Value*|
|Total Fat 31g||39%|
|Saturated Fat 4g||18%|
|Total Carbohydrate 66g||24%|
|Dietary Fiber 11g||41%|
|Total Sugars 22g|
|Vitamin C 61mg||306%|
|*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.|