Soak Fresh Mussels (4 pound) in cool water for about 20 minutes to remove sand and grit. Drain water.
Under running water, wash each mussel and gently scrub with a nylon brush, removing debris, barnacles, etc. Pull out any beards.
Make sure all mussels are completely closed. If any are slightly open, tap them with your fingernail or against the side of the sink. If they close up, they are good to go. If they remain open, they are dead - discard them.
Place stockpot or wide skillet over medium heat. Add Butter (2 tablespoon) to the pot. Once melted, add Shallot (2) and sauté until soft and just beginning to brown.
Add Dry White Wine (2 cup) to the pan and bring to a boil. Reduce heat to medium, add a pinch of Kosher Salt (to taste), then add all mussels. Cover the pot and allow to steam for 5 minutes, shaking the pan occasionally.
Check after 5 minutes to see if all mussels are open. If not, return the lid to the pot and steam for 2 more minutes.
Remove lid, add Butter (2 tablespoon), swirl, and stir. Remove any mussels that have not opened. Do not eat a mussel that didn't open! Transfer mussels to serving bowls, spoon sauce over them, top with Italian Flat-Leaf Parsley (to taste). Serve with crusty bread.