Pat the chicken thighs dry with paper towels. Season both sides generously with salt, black pepper, and paprika. Set aside.
Heat 2 tablespoons of butter in a skillet over medium-high heat. Add chicken thighs skin side down and sear for 5-7 minutes until golden and crispy. Flip and cook 3-4 minutes more. Remove chicken and set aside.
Reduce heat to medium. Add remaining 2 tablespoons butter, then sauté diced onion for 3-4 minutes until translucent. Stir in minced garlic and cook for 30 seconds to 1 minute, careful not to burn.
Add long-grain rice to skillet and stir to coat with garlic butter and onions. Pour in chicken broth and bring to a gentle simmer.
Place seared chicken thighs on top of rice. Cover skillet with lid, reduce heat to low, and cook for 20-25 minutes until rice is tender and chicken is cooked through (165°F/74°C internal temperature).
In the last 5 minutes, sprinkle frozen peas over rice and chicken. Replace lid and let peas steam. When done, sprinkle chopped fresh parsley over the dish.
Serve hot and enjoy the perfect balance of crispy chicken, garlicky butter, and fragrant rice.