These spiral sweet potatoes are roasted in a cast iron skillet with garlic, rosemary, and a little brown sugar. The slices are shingled in a shallow spiral, so each one shows an exposed top edge that can brown in the oven. Soft centers, browned edges, and a caramel note from the sugar are the goal.
Roasted spiral sweet potatoes work as a side dish for a holiday table or a weeknight dinner. The recipe uses a 10½- to 11-inch ovenproof dish and serves 6.
Test the potatoes before the second stage of baking. The overlapping slices should be nearly tender by then. That leaves enough oven time for the tops to brown while the thicker layers finish underneath.
For a different way to roast sweet potatoes, try my Parmesan-crusted sweet potatoes, which have a buttery, golden cheese crust.
Servings: 6 as a side dish
Prep time: 20 minutes
Cook time: 50–65 minutes
Total time: 1 hour 10 minutes–1 hour 25 minutes
Equipment: 10½- to 11-inch (27–28 cm) ovenproof skillet, preferably cast iron
Ingredients
-
2¾ pounds (1.25 kg) orange-fleshed sweet potatoes, weighed before peeling; about 2¼ pounds (1 kg) after peeling and trimming
-
3 tablespoons (42 g) unsalted butter, melted
-
1 tablespoon packed light brown sugar (13 g)
-
2 tablespoons (30 ml) olive oil, divided, plus about 1 teaspoon for greasing the skillet
-
3 medium garlic cloves, finely grated
-
2 teaspoons finely chopped fresh rosemary
-
1 teaspoon fine sea salt
-
¼ teaspoon freshly ground black pepper
-
½ teaspoon finely grated lemon zest, optional, for serving
-
A small pinch of flaky sea salt, optional, for serving
Instructions
-
Set a rack in the middle of the oven. Heat to 350°F (180°C) for a conventional oven, or 320°F (160°C) for a fan oven. Brush the bottom and sides of the skillet with the extra teaspoon of olive oil.
-
Peel the sweet potatoes, trim the ends, and slice crosswise into rounds about ⅛ inch (3 mm) thick. A mandoline gives consistent slices; use its hand guard. Keep the smaller rounds for the center of the skillet.
-
In a large bowl, stir the brown sugar into the warm melted butter. Mix in 1 tablespoon of the measured olive oil, the garlic, the rosemary, the salt, and the pepper. Add the potato slices and turn them gently through the mixture. Separate any slices that stick together so both sides get coated.
-
Start against the outside wall of the skillet and overlap the slices around the edge, leaning them at a shallow angle. Continue with smaller rings toward the center. Keep the upper edges visible and leave enough room to nudge the slices apart rather than compressing them into a tight stack. Scrape any seasoning left in the bowl over the potatoes.
-
Seal the skillet tightly with foil and bake for 30 minutes. Carefully lift the foil and push a thin knife through several overlapping slices near the center. It should enter with only slight resistance. If the potatoes still feel firm, reseal the foil and bake for another 5–10 minutes before checking again.
-
Remove the foil and brush the tops with the remaining 1 tablespoon olive oil. Increase the oven to 425°F (220°C) conventional, or 400°F (200°C) fan, and return the uncovered skillet to the oven. Bake for approximately 20–25 minutes. Check the color after 15 minutes, since the brown sugar can darken quickly. Rotate the pan if one side browns faster. The potatoes are ready when the exposed edges are golden to deep brown and a knife slides easily through the center.
-
Add the lemon zest, if using, and taste before adding any flaky salt. Serve promptly, scooping down through the layers to include both the browned tops and the soft potatoes underneath.
Tips for Tender Layers and Browned Edges
The rounds can differ in diameter, but keep the thickness consistent. Thicker slices need more time to soften. Tuck smaller rounds into gaps without building a thick mound in the middle.
A shallow, overlapping arrangement gives the oven more surface to brown. Avoid squeezing the slices tightly together.
The brown sugar encourages browning, so watch the color during the final bake. If the tops become dark while the lower layers are still firm, cover the skillet again, reduce the oven to the first-stage temperature, and continue baking until tender.
For dried rosemary, use ⅔ teaspoon in place of the fresh, crushing it between your fingers before adding it to the butter.
The optional lemon zest adds a fresh citrus note that works well with the butter and rosemary. Sprinkle it on after baking.
What to Serve With It
Serve the skillet with roast chicken, turkey, or air fryer pork tenderloin. Green beans or a salad with a sharp vinaigrette go well alongside the sweet potatoes.
Storage and Reheating
Transfer leftovers to a shallow container and refrigerate within 2 hours, or within 1 hour if the temperature is above 90°F (32°C). Keep refrigerated at 40°F (4°C) or below and use within 3–4 days.
Reheat portions in a shallow, lightly oiled baking dish at 350°F (180°C) until they reach 165°F (74°C) throughout. Start checking after 10 minutes. The edges soften during storage, though oven reheating can restore some browning.
