Fish Pie with Dubliner Cheese Rösti Topping from Clodagh's Suppers - Cooking by the Book

Ingredients

• 1 pound Idaho or Russet potatoes
• 2 ounces aged Dubliner cheese
• 9 ounces skinless smoked haddock fillet
• 9 ounces skinless salmon fillet
• 3 ½ ounces raw, peeled shrimp
• 1 ¼ cups whole milk
• 1 shallot, peeled and halved
• 1 bay leaf
• 1 teaspoon black peppercorns
• 5 tablespoons butter, softened ‘
• ½ cup all-purpose flour
• 2 teaspoons Dijon mustard
• Sea salt and freshly ground black pepper
• 2 tablespoons chopped dill