Step 1: Preheat your oven to 400°F (200°C). Pat the chicken thighs dry with paper towels and season generously with salt and black pepper.
Step 2: Heat olive oil in a large oven-safe skillet (preferably cast iron or a heavy-bottomed pan) over medium-high heat. Sear the chicken thighs skin-side down for 5-7 minutes, until the skin is golden brown and crispy. Flip and sear for another 2-3 minutes. Remove chicken from the pan and set aside, leaving the rendered fat in the skillet.
Step 3: Reduce heat to medium. Add chopped onion and bell peppers to the skillet and sauté for 5-7 minutes until softened. Add minced garlic, smoked paprika, and saffron threads (if using) and cook for another minute until fragrant, stirring constantly.
Step 4: Stir in the Arborio or paella rice, ensuring each grain is coated in the flavorful pan juices and spices. Cook for 1-2 minutes, stirring, to toast the rice slightly.
Step 5: Pour in the chicken broth and crushed tomatoes. Add salt and pepper to taste. Bring the mixture to a simmer, scraping up any browned bits from the bottom of the pan.
Step 6: Nestle the seared chicken thighs back into the rice mixture, skin-side up. Make sure the chicken is partially submerged but the skin remains above the liquid to crisp up.
Step 7: Transfer the skillet to the preheated oven and bake for 25-30 minutes, or until the rice is tender, the liquid has been absorbed, and the chicken is cooked through (internal temperature of 165°F or 74°C).
Step 8: Once cooked, remove the skillet from the oven. Let it rest for 5-10 minutes, covered loosely with foil, before serving. This allows the flavors to meld and the rice to finish absorbing any remaining liquid.
Step 9: Garnish with fresh parsley or cilantro and serve hot with lemon wedges, if desired.