Active Time

　　10 min

　　Total Time

　　1 1/4 hr

　　If you've never had pale-fleshed Japanese sweet potatoes before, you'll be surprised by their subtler, drier flesh, which tastes unmistakably of chestnut. A bit of miso mixed into the scallion butter stealthily rounds out the interplay of sweet and umami that will have you eating all the way through to the last flaky remnants of skin.

　　

Ingredients

Makes 8 servings

　　8 small slender Japanese or Garnet sweet potatoes (4 to 5 pounds total)

　　1 1/2 sticks unsalted butter, well softened

　　1 1/2 tablespoons miso paste (preferably white)

　　3 tablespoons finely chopped scallion

　　

Step 1

Preheat oven to 450°F with rack in upper third.

　　

Step 2

Prick potatoes all over with a fork and put on a foil-lined large baking sheet. Bake until very soft when squeezed, 45 minutes to 1 hour.

　　

Step 3

While potatoes bake, stir together butter, miso, and scallion until combined.

　　

Step 4

Slit hot potatoes lengthwise and, using oven mitts, push in sides to puff up potato. Serve with some scallion butter in center of each and with additional scallion butter on the side.

　　Cooks' notes:

　　· Scallion butter can be made 4 days ahead and chilled, covered. Bring to warm room temperature and stir before using.

　　· Sweet potatoes can be roasted (but not cut) 4 hours ahead and kept at room temperature, covered with foil. Reheat potatoes on a baking sheet on middle rack of a 350°F oven until heated through, about 20 minutes.