In a 4 quart pot, add the water, white wine or extra water, salt, parsley and lemon. Bring the pot to a simmer over medium heat.
Add a steamer basket or metal colander to the pot that fits inside but doesn't touch the water, turn the heat down as low as it will go, and add the shrimp. It's okay if they are piled in together.
Cover the pot with a lid to make a tight seal and simmer 2 minutes, remove the lid and stir the shrimp to ensure even cooking then cover and cook 2 minutes more depending on the size of the shrimp.
Transfer the shrimp to a plate to cool or you can drop them briefly into a bowl of ice water to stop the cooking. Once the shrimp are cooled to room temperature, refrigerate until ready to serve.
Serve with cocktail sauce and sliced lemons.