· 1/2 cup finely chopped tarragon (leaves and tender stems), plus 4 whole sprigs· 2 garlic cloves, finely grated or minced· 2 tablespoons extra-virgin olive oil, more for drizzling· 1 1/2 teaspoons kosher salt, more as needed· 1/2 teaspoon ground black pepper, more as needed· 3 pounds bone-in chicken thighs (skin on)· 2 large onions, peeled and sliced (about 4 cups)· 4 thyme sprigs· Sherry vinegar, to taste
Step 1In a large bowl, stir together tarragon, garlic, oil, salt and pepper. Add chicken thighs and toss to coat. Cover with plastic wrap and chill for at least 6 hours, and up to overnight.Step 2Heat oven to 425 degrees. Spread onions out on a rimmed baking sheet, drizzle with oil and sprinkle with salt and pepper and toss well. Clear spaces on the baking pan, then place chicken pieces in the cleared spaces so the onions surround the chicken. Strew thyme and tarragon sprigs over onions and chicken.Step 3Roast, tossing the onions after 15 minutes, until chicken is cooked through and the onions tender, 25 to 35 minutes. If the chicken skin or onions are not as brown as you’d like, run pan under the broiler for 1 to 2 minutes at the end of cooking.Step 4Place chicken on a platter. Drizzle onions with sherry vinegar and more salt and pepper if needed. Spoon onions around the chicken and serve.