Step 1

Pat the chicken dry and place in a large bowl or large ziptop bag. Add the garlic, 2 tablespoons oil, Italian seasoning, rosemary, lemon zest and juice (zest the lemon right over the bag or bowl), 1 teaspoon salt, and 1/4 teaspoon pepper. Toss the chicken (or seal the bag and turn to coat). Let sit at room temperature for at least 30 minutes and up to 1 hour or cover and refrigerate for up to 12 hours.

Step 2

When ready to bake, preheat the oven to 425 degrees F. Thinly slice the onions and place in a 9x13 or similarly sized roasting pan or casserole dish.

Step 3

Drizzle the onions with the remaining 1 tablespoon oil, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Toss to coat.

Step 4

Remove the chicken from the marinade and shake off any excess. Clear some spaces in the onions for the chicken, then nestle it in.

Step 5

Bake the chicken thighs for 15 minutes. Remove the pan and toss the onions to promote even cooking (I use a fork to stir them around a bit). Return to the oven and bake for 10 to 20 additional minutes (that’s 25 to 35 minutes total), until the internal temperature of the chicken reaches 155 to 160 degrees F (chicken is considered cooked at 165 degrees F, but its temperature will continue to rise as it rests). If you’d like to brown the chicken skin further, at the end of the cooking time, place the pan under the broiler for 1 to 2 minutes (watch closely!).

Step 6

Remove the chicken to a serving plate. Cover and let rest 10 minutes. Stir the onions in the pan, spread them into an even layer, then return them to the oven to roast further while the chicken rests. The onions will become jammy and a few might look a little crispy.

Step 7

Remove the onions from the oven, then stir the vinegar into them. If desired, return the chicken to the pan and place under the broiler for crispy skin.

Step 8

Serve the chicken thighs warm, with onions spooned over the top. Sprinkle with fresh herbs.