To a large bowl add 1 quart of cool water, 1 ½ tablespoons of the salt, the lemon juice, and 1 ½ teaspoons of the liquid crab boil. Stir to dissolve the salt. Add 2 quarts of ice to the bowl and set aside.

Fill a large (4- to 6- quart) pot about two-thirds full with water and bring to a boil over medium-high heat. Stir in the shrimp and cook only until the shrimp turn pink, curl up and are just cooked through, usually only about 4 minutes after being added. Take care not to overcook. If the shrimp are small, they may be cooked through even before the water returns to a boil. Using a slotted spoon, immediately transfer the shrimp from the hot water to the seasoned ice bath. Allow the shrimp to chill in the ice bath – they will soak up the seasonings and be perfectly seasoned once they’re drained.

Add the remaining salt and remaining liquid crab boil to the hot water remaining in the pot, add the potatoes and cook until tender when pierced with a knife, usually 15 to 20 minutes, depending on their size.  Remove and set aside to cool. Add the corn to the pot and cook until the kernels are crisp-tender, 3 to 5 minutes. Remove and set aside until you’re ready to serve the shrimp.

Remove the shrimp from the ice bath and serve immediately with the potatoes, corn, and dipping sauce if desired. Shrimp may be prepared in advance and refrigerated in airtight containers for up to 3 days if desired.