Gravlax with Mustard Sauce

Name: Gravlax with Mustard Sauce
Prep time: 15 min
Total time: 15 min
Cuisine: European
Ingredients: 3 pounds fresh salmon, center cut; 1 large bunch of dill, plus 1/4 cup chopped dill for serving; 1/2 cup kosher salt; 1/2 cup sugar; 2 tablespoons white peppercorns, crushed; 1 tablespoon whole fennel seeds; Pumpernickel bread, for serving; Mustard Sauce, recipe follows