
In a large paella pan or wide skillet, heat olive oil over medium-high heat. Add chicken pieces and chorizo, and cook until browned on all sides. Remove from pan and set aside.
Add chopped onion, bell pepper, and garlic to the pan. Sauté until softened, about 5 minutes. Stir in tomato paste and cook for another minute.
Add the paella rice to the pan and stir to coat with the vegetables and oil. Cook for 2-3 minutes, allowing the rice to lightly toast.
Pour in chicken broth and add saffron threads. Season with smoked paprika, salt, and pepper. Bring to a boil, then reduce heat to low, cover, and simmer for 20 minutes, or until the rice is almost cooked through.
Arrange the browned chicken and chorizo over the rice. Add shrimp and mussels, pushing them slightly into the rice. Cover and cook for another 10-15 minutes, or until the seafood is cooked and the rice is tender. Do not stir the paella during this time to allow the socarrat to form.
Remove from heat and let the paella rest for 5-10 minutes before serving. Garnish with fresh parsley and lemon wedges. Serve hot.
Optional: For a richer flavor, add a splash of dry white wine to the vegetables while sautéing.