Mussels with Roasted Potatoes

Name: Mussels with Roasted Potatoes
Ingredients: 4 large Yukon Gold or russet (baking) potatoes (2 pounds total); 6 tablespoons extra-virgin olive oil; 1/2 tablespoon kosher salt; 1/3 cup finely chopped shallot; 3 garlic cloves, minced; Rounded 1/4 teaspoon dried hot red pepper flakes; 1 cup dry white wine; 3/4 cup water; 2 pounds mussels (preferably cultivated), scrubbed well and beards removed; 3 tablespoons chopped fresh parsley