Preparation:
Cut cod into 1 1/2-inch pieces. Rinse scallops with running cold water to remove sand from crevices; slice each scallop horizontally in half. Shell and devein shrimp; rinse with running cold water. With stiff brush, scrub clams and mussels under running cold water to remove any sand; remove beards from mussels. Rinse leeks to remove sand; cut into 3/4-inch pieces.
In 8-quart Dutch oven or saucepot over high heat, heat 1 cup water to boiling; add clams and mussels; heat to boiling. Reduce heat to medium; cover and cook until shells just open, about 5 minutes, stirring occasionally.
With slotted spoon, remove clams and mussels to large bowl. Rinse each clam and mussel in cooking broth to remove any sand. Let broth stand until sand settles to bottom of Dutch oven. Pour clear broth into bowl; discard remaining broth. Wipe Dutch oven dry.
In same Dutch oven over medium heat, in hot oil, cook leeks and garlic until leeks are tender. Add tomatoes with their liquid, salt, thyme, saffron, 2 cups water, and reserved clam broth; heat to boiling.
Add cod, shrimp, and scallops; heat to boiling. Reduce heat to medium-low; cook, uncovered 5 to 8 minutes, until fish flakes easily, shrimp turn pink and scallops are opaque. Add clams and mussels; heat through. |