Bring a large pot of water to a boil. Add salt to the water and Old Bay Seasoning. You can also add a lemon cut in half and squeeze the juice into the pot.
When the water is boiling add large shrimp with the tail and shells on.
By the time the water starts boiling again the shrimp should be pink & floating to the top (about 2-3 minutes).
Put into a bowl with ice water. Shell & serve with cocktail sauce (A mixture of ketchup, horseradish, relish, lemon juice, hot sauce & a dash of worcestershire sauce).

