Chili-Spiced Chicken Thighs and Potatoes

Adjust oven racks to lowest and top positions and heat oven to 450 degrees. Combine 1½ teaspoons salt, chili powder, paprika, pepper, garlic powder, and cayenne in small bowl. Bring 2 quarts water to boil in Dutch oven.

Place 1 thigh skin side down on cutting board. Cut away any pockets of fat and any skin that extends beyond meat and reserve trim. Make three ½-inch-deep slits in flesh parallel to bone. Turn skin side up. Repeat with remaining thighs. Using tip of paring knife, poke skin of each thigh 8 to 10 times. Sprinkle 1½ teaspoons spice mixture evenly over skin of thighs. Turn thighs over and sprinkle remaining spice mixture over flesh side. Rub mixture into slits.

Scatter trim over surface of rimmed baking sheet. Roast on lower rack until trim is mostly crisped and fat is rendered, 8 to 10 minutes. Discard trim and leave fat in baking sheet. While trim is rendering, add potatoes and baking soda to boiling water and return to boil. Boil for 2 minutes and drain well. Return potatoes to Dutch oven and place over low heat. Cook, shaking pot occasionally, until any surface moisture has evaporated, about 2 minutes. Remove from heat.

Add rendered fat and remaining 2 teaspoons salt to potatoes and stir with rubber spatula until potatoes are coated with starchy paste, about 30 seconds. Transfer potatoes to now-empty sheet pan and spread into even layer. Roast on lower rack until undersides of potatoes are brown and crisp, about 15 minutes.

Using thin metal spatula, flip potatoes. Push potatoes aside to clear 1 space for each thigh. Place thighs skin side up in cleared spaces. Roast on upper rack until chicken is browned and crisp and largest thigh registers at least 185 degrees, 25 to 30 minutes, rotating pan halfway through roasting.

Transfer thighs to platter to rest. Stir potatoes to coat with any remaining liquid and spread over surface of baking sheet. Return pan to upper rack and roast until potatoes are mostly dry, about 5 minutes. Transfer to platter with chicken and sprinkle potatoes with scallion. Serve, passing lime wedges separately.