Heat the chicken broth in a saucepan, adding the saffron threads. Allow it to steep while you prepare the rest of the ingredients.

In a large paella pan or a wide frying pan, heat the olive oil over medium heat. Add the chopped chicken thighs, seasoning with salt and smoked paprika. Cook until browned and fully cooked, about 8-10 minutes. Remove from the pan and set aside.

In the same pan, add the onion and garlic, cooking until soft and fragrant, about 3 minutes. Toss in the bell peppers and continue cooking for another 5 minutes until they're tender.

Stir in the rice, allowing it to toast slightly with the vegetables for about 2 minutes.

Pour in the hot broth mixture, add the cooked chicken back into the pan, and bring to a boil. Reduce the heat to a simmer.

Let the paella cook uncovered for about 15-20 minutes, without stirring, until the rice absorbs the liquid and starts to develop a nice crust on the bottom.

Nestle the shrimp and mussels into the rice, adding the frozen peas last. Cover the pan with foil or a lid and allow it to cook for an additional 5-7 minutes, or until the shrimp are pink and mussels have opened.

Once cooked, remove from heat and let it sit, covered, for about 5 minutes. Garnish with fresh parsley and serve with lemon wedges.