Step 1

Arrange a rack in the middle of the oven and heat the oven to 350℉.

Step 2

Dice 1 small yellow onion (about 2/3 cup). Mince 3 garlic cloves. Pat 4 bone-in, skin-on chicken thighs dry with paper towels, then season all over with 1 teaspoon of the kosher salt and 1/4 teaspoon black pepper.

Step 3

Place the chicken skin-side down in a single layer in a 10-inch cast iron or oven-safe skillet over medium-high heat and cook until the skin is crisp and golden-brown, 7 to 9 minutes. Flip the chicken and cook until the second side is golden brown, 3 to 4 minutes. Transfer the chicken to a plate; it will not be cooked through.

Step 4

Reduce the heat to medium. Add the onion to the skillet and cook, stirring occasionally, until softened, about 3 minutes. Add the garlic and cook until fragrant, about 30 seconds. Add 1 cup long-grain white rice, 2 teaspoons dried Italian seasoning, 1/4 teaspoon red pepper flakes if using, and the remaining 3/4 teaspoon kosher salt. Stir to combine and cook until toasted, about 2 minutes.

Step 5

Add 1 (14.5-ounce) can fire-roasted diced tomatoes and their juices and 1 1/2 cups low-sodium chicken broth. Stir, scraping the bottom of the pan with a wooden spoon to release any stuck-on bits, and bring to a boil. Remove the pan from the heat. Return the chicken to the pan skin-side up on top of the rice and pour in any accumulated juices on the plate.

Step 6

Transfer the skillet to the oven and bake until the chicken is cooked through and the rice is tender, 18 to 25 minutes. Transfer the chicken to plates. Add 1 teaspoon balsamic vinegar to the rice and stir to combine. Serve the rice with chicken. Garnish with chopped fresh parsley leaves if desired.