This is a recipe that I adapted a bit from Bon Appétit: I don’t have a cast iron skillet, so I just used the one that goes in the oven up to 500 °F, and the results made me very happy. I may not have gotten the same amount of color or caramelization as I would have otherwise, but these potatoes were delicious nonetheless (they’re basically vegetable candy). The mix of mirin and honey worked really well! I got my white sweet potatoes at Whole Foods, which usually has a selection of 4-5 different kinds, but I think orange sweet potatoes would be just as good. I served them with Asian barbecued pork, though Bon Appétit recommends roast duck or pork chops.
2 large white sweet potatoes (about 2 lbs. total)
½ cup mirin (sweet Japanese rice wine)
2 Tbsp. honey
1 Tbsp. distilled white vinegar
½ tsp. kosher salt
2 tsp. corn oil (I used safflower oil, I think)
2 Tbsp. unsalted butter (vegan margarine would be okay)
coarse sea salt (preferably Maldon)
Preheat oven to 450 °F. Place a well- seasoned 8"–10" cast-iron skillet in oven.
Pierce potatoes in several spots with a fork. Microwave sweet potatoes on high for 5 minutes. (Alternatively, wrap sweet potatoes in foil and bake at 450 °F until tender around edges but still hard in center, 30–35 minutes.) Transfer potatoes to a large bowl and cover with plastic wrap. Let sit for 5 minutes.
Whisk mirin, honey, vinegar, and salt in a medium bowl. Peel sweet potatoes and cut crosswise into 1"–1½"-thick rounds. Add to mirin mixture; toss to coat.
Using oven mitts, carefully remove heated skillet from oven; add oil and swirl pan to coat. Add sweet potatoes and mirin mixture to skillet, arranging potatoes cut side down. Bake until sweet potatoes are caramelized on one side, 15–20 minutes. Turn sweet potatoes, rotating them around pan to avoid hot spots, and cook until tender and caramelized, 5–7 minutes longer.
Transfer sweet potatoes to a platter. Add 2 Tbsp. water to skillet, scraping up browned bits. Add butter, swirling pan to melt and combine. Pour sauce over sweet potatoes. Season with salt.