Into a large bowl, finely grate garlic or press with a garlic press. With a whisk, mash and combine anchovies with garlic until pasty. Whisk in lemon juice and vinegar. Gradually whisk in oil. Season with salt and pepper to taste. Set aside.
Cover and heat a medium pot of water to a boil on high. Season generously with salt. Reduce heat to a simmer. Add squid and simmer 2 to 3 minutes, until opaque. With a slotted spoon, transfer to a colander set in sink and rinse with cold water to cool. To simmering water, add scallops and cook 2 to 3 minutes, until opaque. Transfer to colander with squid and rinse with cold water.
To simmering water, add shrimp. Simmer 2 to 3 minutes, until cooked through. Transfer to colander with squid and scallops and rinse with more cold water. Drain seafood well and add to large bowl with dressing.
Carefully discard most of water in pot, leaving about 2". Return to a simmer on medium and add cod. Cook 4 to 5 minutes, until firm and cooked through. With slotted spoon, transfer to a medium bowl. To same pot, add mussels. Cover and cook 3 to 4 minutes, until all the shells have opened (discard any mussels that do not open). Remove pot from heat and let stand until cool enough to handle, then remove mussels from shells and add to large bowl with squid, scallops and shrimp.
To large bowl with seafood, add celery, clams and parsley. Toss until well combined. Season with salt and pepper to taste. Add cod and gently toss to combine. Refrigerate, covered, at least 2 hours or up to 4 hours.
Source: Hannaford fresh Magazine, December 2023