These are creamier and more flavorful sweet potatoes—thanks to science, and thanks to Nik Sharma, whose new cookbook The Flavor Equation breaks down the research on how we can make our food more delicious. In this case: a surprisingly simple one-pan technique for first steaming then roasting that makes sweet potatoes the best version of themselves—perfect for a splashy Thanksgiving side or just: dinner.
As Nik writes in The Flavor Equation, “We all adore certain pantry staples. Kefir and crème fraîche are two of my favorites. I’ve been testing new ways to improve on roasting sweet potatoes in the oven, and I found that a combination of steaming and roasting works great for a dish like this for both the texture and the extra set of aroma molecules that comes through. The first step, partial steaming, keeps the moisture inside the sweet potato while cooking, and the second step, uncovered roasting, helps create a robust flavor profile. I recommend using fragrant nuts. Toasted hazelnuts are a good substitute for the peanuts.
“The Flavor Approach: Butter works as the fat of choice here due to its higher smoke point. As the butter melts, it separates into its constituents—fat, water, sugars, and milk solids—which undergo caramelization and the Maillard reaction. The sugars concentrate as the water evaporates during cooking. Fish sauce adds a spot of umami to the sauce, but you can use vegan fish sauce as an alternative. The peanuts and scallions provide crunch against the softer textures of the potato and the dressing.”
A few more tips: If your sweet potatoes are much larger than 7 ounces each, extend the steaming time in step two until they’re starting to noticeably soften, before roasting uncovered in step three—you also might want to line the pan with foil, parchment, or a nonstick baking mat, as more sticky juices will collect. And use any leftover maple crème fraîche to dunk other vegetables, as a creamy salad dressing, or to perk up other sleepy carbs like rice or regular potatoes.
Recipe adapted very slightly from The Flavor Equation (Chronicle Books, October 2020).
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- Prep time 15 minutes
- Cook time 40 minutes
- Serves 4
- For the sweet potatoes:
sweet potatoes (each 7 ounces [200 grams]), preferably a yellow-fleshed variety such as Garnet or Jewel
unsalted butter, at room temperature
Fine sea salt
- For the dressing & garnish:
(120 grams) crème fraîche or sour cream
maple syrup or honey
freshly squeezed lime juice
fish sauce (optional, see Author Notes)
freshly ground black pepper
Fine sea salt
thinly sliced scallions, both green and white parts
red chile flakes, such as Aleppo, Maras, or Urfa
- To prepare the sweet potatoes, heat the oven to 400°F (200°C).
- Rinse and scrub the sweet potatoes under running tap water. Slice them lengthwise and place them in a roasting pan, cut side facing up. Brush or smear with the butter and season with salt. Cover the pan with a sheet of aluminum foil and press around the edges to seal snugly. Bake for 20 minutes.
- After 20 minutes, remove the foil, flip the sweet potatoes, and cook, uncovered, for 20 minutes more, until the sweet potatoes are cooked thoroughly and are tender; a knife inserted into the center of the sweet potato should slide through easily. Remove from the heat and let rest for 5 minutes.
- To prepare the dressing, in a small bowl, combine the crème fraîche, maple syrup, lime juice, fish sauce, if using, and pepper. Taste and season with salt.
- To serve, top the warm roasted potatoes with a few tablespoons of the maple crème fraîche dressing. Sprinkle with the scallions, peanuts, chile flakes, and lime zest. Serve with the extra dressing on the side.