How to Make It
In a large nonstick skillet, heat the olive oil. Season the cod fillets and shrimp with salt and pepper and cook over moderately high heat until they are browned and cooked through, about 3 minutes per side. Transfer the seafood to 4 bowls and keep warm.
Add the sugar to the skillet and cook, stirring frequently, until the sugar starts to melt, about 1 minute. Add the curry paste and cook, stirring, until the paste is fragrant and bright red, about 1 minute. Add the green beans, carrot, 2 cups of the chicken broth and the coconut milk and bring to a simmer. Add the mussels and cook over moderately high heat until the mussels open, 1 to 2 minutes. With a slotted spoon, transfer the mussels to the bowls with the cod and shrimp.
In a small bowl, whisk the arrowroot with the remaining 1 cup of chicken broth, add to the skillet and bring to a simmer over moderately high heat. Add the peas and cook until they are heated through, about 3 minutes. Season the sauce with salt and pepper and stir in the cilantro. Pour the sauce and vegetables into the bowls and serve with lime wedges.