I know it's ridiculous to call a recipe "the best," buuuuttttttt this recipe is THE BEST shrimp cocktail. I've never met anyone who thought differently once they'd tried it. The poaching method gives the shrimp a wonderful, delicate texture and flavor, and the sauce has a hint of gin in it, so HI. You can make the sauce and shrimp a day in advance and just stir the parsley into the sauce and arrange it all on a platter right before serving.
Mix together the ketchup, horseradish, tabasco, gin, celery salt, salt and lemon juice. Chill until ready to serve. Stir in parsley right before serving.
Peel and devein shrimp, leaving tails attached. Place peels into a large pot. Add water, 1 tablespoon of the salt, wine or vermouth, peppercorns, coriander seeds, bay leaves, onion, tarragon and lemon. Bring to a boil, then reduce heat and simmer uncovered for 20 minutes. Remove from heat and let sit 30 minutes more, then strain broth through a fine sieve into a fresh pot.
You can ask the fishmonger to peel and clean the shrimp for you. Just ask them to leave the tails attached and to give you the shells.
Save the delicious stock to use in risotto if you like.