1) Scrub mussels with a stiff brush, discard any that are open and stay that way even when you close the shell. Discard any with broken shells.Soak them in cool clean water for at least an hour. Mussels are alive and breathing and have taken in sand over time. This allows them to expel the sand.Mussels have a small fibrous "beard" that should be removed. Pull it out toward the hinge of the shell to keep from injuring the mussel.

2) Heat the olive oil in a large pot over medium-high heat.

3) Add the shallots and garlic and cook until soft, about 5 minutes.

4) Add the mussels, wine, buttermilk, butter, and parsley and season well with the kosher salt. Give it a good stir, cover the pot, and cook until mussels open and are cooked through, 10 to 15 minutes. Divide the mussels and the juices between 2 bowls and serve with a crusty whole-grain bread to sop up that wonderful sauce.