Fill a large stock pot with 8 cups of water (2 quarts). Squeeze the juice of one lemon into the water, and then add the lemon halves into the water as well. Bring the water to a boil, and then turn the heat down to a simmer. Add the shrimp (shells on), cover the pot with a lid, and let the shrimp poach for 4-5 minutes. Watching your timer, at four minutes, check the shrimp for done-ness, they will be pink and firm. Immediately turn the heat off. Cover the pot one more time and keep the shrimp in the water for about two minutes longer. Remove the shrimp from the water, placing them on a parchment lined sheet pan to cool. Do not rinse them. Once the shrimp have cooled enough to handle, remove the shells and devein all of them, leaving the shrimp tails on. Move to a covered bowl to chill for a minimum of two hours before serving.

In a small bowl mix together the ketchup, horseradish sauce, Worcestershire sauce, dijon mustard, Tobasco sauce, apple sauce and lemon zest. Stir all together until combined and the sauce is smooth. Serve cold with the chilled shrimp.

Serve the shrimp on a platter with the cocktail sauce in a small bowl. Serve over crushed ice, lemon wedges and on a bed of green leaf lettuce for added color.