Marinate the Shrimp: In a medium bowl, combine the shrimp with lime juice, sweet paprika, ½ tsp salt, and optional black pepper. Mix well, ensuring the shrimp are evenly coated. Let the shrimp marinate while you prepare the base of the stew, about 10 minutes.

Sauté the aromatics: Heat the olive oil in a large pot or deep skillet over medium heat. Add the chopped white onion and cook, stirring frequently, until soft and translucent, about 5 minutes. Avoid browning the onions.

Prepare the Base: Add the cannellini beans to the pot, stirring gently to combine them with the onions. Pour in the fish or vegetable broth and add the sprigs of rosemary. Bring the mixture to a gentle simmer, allowing the flavors to meld for about 5 minutes. Season with the remaining ½ tsp salt and adjust to taste.

Cook the Shrimp: Reduce the heat to low. Remove the rosemary sprigs and discard. Add the marinated shrimp, including any leftover marinade, to the pot. Stir gently to distribute them evenly in the stew. Allow the shrimp to cook for 2–4 minutes, just until they turn pink and opaque. Avoid overcooking.

Serve and Enjoy: Ladle the stew into bowls. Garnish with an extra rosemary sprig or a drizzle of olive oil if desired.