In a large stockpot filled with 1 gallon of water add 1/2 c. kosher salt and 1 3 oz. bag of Zatarain's shrimp boil. Cut a lemon in half and squeeze all of the juice into the pot. Also, place the lemons in the pot with the water.

Bring the poaching liquid to a boil. (This happens faster if you cover the pan with a lid.) Simmer the spice bag for about 15-20 minutes to flavor the broth.

Lower the broth to a gentle simmer. Only tiny bubbles should float to the surface of the broth, or use a thermometer to confirm that the poaching liquid is 160-180 degrees.

Pour the shrimp into the poaching liquid. Poaching shrimp should take about 5-7 minutes regardless of if they are frozen or not. (Frozen shrimp take 1-2 min longer on average.) Remove the shrimp when they are in the shape of soft "C's". (As in the letter C in the alphabet.)

Immediately remove with a slotted spoon or spatula to a baking sheet. Spread out the shrimp so that they can rapidly cool. You can also place them into a refrigerator to stop the cooking process.

Peel and enjoy or use them in a variety of recipes.