Mussels Recipe Without Wine - 1 large shallot, finely chopped, 1/4 onion, finely chopped (about 1/3 cup), 1/4 cup dry white wine, 3 1/2 tablespoons unsalted butter, cut into 1/2 cubes, 1 tablespoon white wine vinegar, 4 1/2 pounds mussels, scrubbed, debearded, freshly ground black pepper.