Bring a pot of water to a boil for the pasta. In a pot large enough to accommodate the mussels heat 2 tablespoons of the butter and gently cook shallots, celery and tablespoons parsley for about 5 minutes. Add the wine and bring to a boil. Add the mussels and raise the heat. When the steam starts to escape, shake the pot, keeping the cover tightly on to rotate mussels inside. Let them cook for 5 to 7 minutes or until the mussels open. Meanwhile, place the pasta in the boiling water and cook for 3 to 5 minutes or until tender. Drain and portion out. Discard mussels that remain closed. Set the open mussels, in their shells, over pasta. Pour the mussel cooking liquid through a fine strainer into a saucepan. Reduce quickly and slightly. Whisk in remaining two tablespoons of butter and parsley. Season to taste with salt and pepper and pour over mussels and pasta.
Recipe courtesy of Michele Urvater