Step 1

Arrange a rack in the middle of the oven and heat the oven to 375℉.

Step 2

Halve and thinly slice 2 medium yellow onions (about 4 cups). Finely grate the zest of 1 small orange until you have 1 teaspoon zest, then juice the orange until you have 2 tablespoons.

Step 3

Pat dry 4 skin-on, bone-in chicken thighs with a paper towel, then season all over with 1 teaspoon of the kosher salt and 1/4 teaspoon of the black pepper. Heat 1 tablespoon of the olive oil in a large cast-iron or ovenproof skillet over medium-high heat until shimmering. Add the chicken skin-side down and sear until golden brown on both sides, 3 to 5 minutes per side. Transfer to a plate.

Step 4

If not a lot of fat has rendered from the chicken thighs, add the remaining 1 tablespoon olive oil to the pan. Add the onions and cook, scraping any browned bits from the bottom of the pan, for 2 minutes. Add 2 packed tablespoons of the brown sugar, 1/2 teaspoon of the kosher salt, and the remaining 1/4 teaspoon black pepper. Reduce the heat to medium and cook, stirring often, until the onions are softened and slightly caramelized, about 6 minutes more.

Step 5

Add 2 cups frozen cranberries, 1 cup dry white wine, 1/2 cup water, 1 packed tablespoon of the brown sugar, 1 tablespoon balsamic vinegar, the remaining 1/2 teaspoon kosher salt, 1/4 teaspoon red pepper flakes, and 1 large fresh basil sprig. Bring to a boil over medium-high heat. Reduce the heat to medium-low and simmer until cranberries soften and liquid thickens, about 5 minutes. Return the seared chicken and any accumulated juices to the skillet, setting the chicken on top of the cranberry and caramelized onion sauce.

Step 6

Bake until the chicken reaches an internal temperature of 165°F, 12 to 20 minutes.

Step 7

Remove and discard the basil sprig. Add the orange zest and 1 tablespoon the orange juice, and stir into the sauce around the chicken pieces. Taste and season with up to 1 tablespoon orange juice and packed 1 tablespoon brown sugar if the sauce is too tart. If the sauce is too thin, transfer the chicken to a clean plate, then simmer the sauce over medium heat until reduced and thickened to your liking, 5 to 10 minutes.

Step 8

Pick the small leaves from the remaining 2 fresh basil sprigs until you have 1/4 cup. (Alternatively, tear the larger leaves into smaller pieces.) Sprinkle over the chicken before serving.