01 - Pat the chicken thighs dry and season both sides evenly with salt, black pepper, and paprika.
02 - Heat olive oil in a large skillet or Dutch oven over medium-high heat. Place chicken thighs skin-side down and sear for 4–5 minutes per side until the skin turns golden brown and crisp. Transfer to a plate and set aside.
03 - Reduce the heat to medium. Melt the butter in the same pan, then add the chopped onion, diced celery, and bell pepper. Sauté for 4–5 minutes until the vegetables soften. Stir in the minced garlic and cook for 1 additional minute until fragrant.
04 - Sprinkle the flour over the sautéed vegetables and stir continuously for 1 minute to cook out the raw flour taste and form a light roux.
05 - Gradually whisk in the chicken broth followed by the milk or cream, stirring constantly to prevent lumps. Add the dried thyme and cayenne pepper if using, then bring the mixture to a gentle simmer.
06 - Stir the rice into the sauce until evenly distributed. Nestle the browned chicken thighs on top of the rice, skin-side up, pressing them slightly into the liquid.
07 - Cover the skillet or Dutch oven with a tight-fitting lid, reduce the heat to low, and cook for 25–30 minutes until the rice is tender and the chicken reaches an internal temperature of 165°F.
08 - Remove from heat and let rest for 5 minutes covered. Garnish with freshly chopped parsley and serve directly from the pan.