Heat the olive oil in a large pot over medium heat. Add the onion, garlic, bell peppers, and cook until softened, about 5 minutes.
Stir in the diced tomatoes, chicken or seafood broth, smoked paprika, and saffron threads. Bring to a boil, then reduce heat to low and simmer for 10 minutes.
Stir in the rice and shrimp. Cover and simmer for 15 minutes, or until the rice is cooked through and the shrimp are pink.
Stir in the mussels and cook for 5 minutes more, or until the mussels are opened.
Stir in the parsley and season with salt and pepper to taste.
Serve hot with crusty bread.
Notes
TipsFor a richer flavor, use homemade chicken or seafood broth.If you don't have saffron threads, you can substitute 1/4 teaspoon of ground saffron.Be sure to discard any mussels that do not open.Arroz Caldoso can be reheated the next day.VariationsThere are many different variations of Arroz Caldoso. Here are a few ideas:Arroz Caldoso de Pollo: This version of Arroz Caldoso is made with chicken instead of seafood. GambarArroz Caldoso de Verduras: This version of Arroz Caldoso is made with vegetables instead of seafood or chicken. GambarArroz Caldoso de Langosta: This version of Arroz Caldoso is made with lobster. GambarArroz Caldoso de Cangrejo: This version of Arroz Caldoso is made with crab.