How to Make It
In a large cast-iron casserole, heat the oil. Add the onion, garlic and the 2 sliced scallions; cook over moderate heat, stirring occasionally, until softened, 7 minutes. Stir in the tomatoes, wine and gochujang and cook, stirring, until the tomatoes just start to break down, about 5 minutes.
Add the clam juice and bring to a boil. Nestle the seafood and tofu in the broth. Cover and cook over moderate heat until the mussels open and the other seafood is opaque, about 7 minutes. Ladle the cioppino into shallow bowls and garnish with scallion. Serve with rice crackers or steamed rice.