If you're starting with raw shrimp, you will need to cook them before proceeding with the recipe. To do so, bring a large pot of salted water to a boil. Once the liquid boils, turn off the heat. Add the shrimp to the hot water and allow the shrimp to poach, uncovered, for a couple of minutes (stirring occasionally) just until they turn pink. While the shrimp cooks, prepare an ice bath by combining cold water and a lot of ice in a large bowl. When the shrimp is just pink and opaque, transfer the shrimp to the ice bath to immediately chill and stop the cooking process. Allow the shrimp to sit in the ice bath for 10 minutes. Drain, pat dry, and peel (if necessary). Pat dry again, cover, and refrigerate until ready to use.