Broiled Whitefish Sandwiches

Ingredients

• 1/2 cup mayonnaise
• 3 tablespoons minced dill pickle
• 2 tablespoons minced red onion
• 1 teaspoon fresh lemon juice
• 1 teaspoon finely chopped fresh tarragon
• Salt and freshly ground pepper
• Four 7-ounce skinless whitefish fillets
• 1 tablespoon unsalted butter, melted
• 1/2 teaspoon dill
• 1/2 teaspoon sweet paprika
• 4 semolina rolls, split
• 4 romaine lettuce leaves
• 4 tomato slices