We got the idea for this simple one-pot meal from the Portuguese bread soup called açorda. Whereas eggs lend açorda substance and richness, this version gets heft from chunks of tender, buttery cod fillets. Bottled clam juice supplies the broth with a briny-sweet flavor. You’ll need a large bunch of cilantro for this recipe; before tossing it into the blender, trim off and discard the bottoms of the stems, then wash and dry the bunch, picking out any damaged sprigs.