1. Melt butter in a large saucepan over medium heat. Add celery and onion and sauté about 4 minutes, stirring often, until vegetables soften. 
2. Sprinkle in flour and cook 1 minute while stirring. Gradually mix in milk and broth, dissolving flour into liquid. 
3. Add potatoes and salt. Bring just to a boil over high heat, stirring often. Reduce heat to low and simmer 5 to 7 minutes, or until potatoes are tender and chowder has thickened. 
4. Add fish and seafood mix and continue to simmer another 5 minutes, or until fish and seafood are just cooked through. 
5. Top with chives and parsley just before serving, and serve chowder with crackers. 

Chef’s secret

You can easily swap fish broth for homemade fish stock.