How to Make It
In a large, heavy saucepan, heat the olive oil. Add the onion, garlic and jalapeño and cook over moderately high heat, stirring, until softened, about 3 minutes. Add the tomato, oregano and saffron and cook for 1 minute, stirring. Sprinkle the flour over the vegetables and stir it in. Add the wine and mussels, cover the pan and cook, stirring, for 1 minute. Add the fish stock, parsley and lemon juice and cook over high heat, stirring, until the mussels open, about 5 minutes. Discard any mussels that do not open. Transfer the mussels and their sauce to deep bowls. Serve at once with crusty bread to soak up the sauce.