Clam chowder
Make a fish stock with prawn heads, carrots, onion, celery, garlic and black pepper. When the stock is ready - after about 30 minutes - add whole milk and cream to taste, add potato and white fish that will hold its shape (halibut or small pieces of monkfish). The clams go in at the last minute, add salt or the brine the clams come packed in, and pepper.