Salmon Cannelloni with Lemon Cream Sauce

Name: Salmon Cannelloni with Lemon Cream Sauce
Ingredients: 2 large eggs; 2/3 cup water; 1/2 cup all-purpose flour; 1/4 teaspoon salt; 1 tablespoon finely chopped fresh tarragon; 3 tablespoons unsalted butter, melted; 2 tablespoons unsalted butter, cut into pieces; 2 tablespoons all-purpose flour; 1 (8-ounce) bottle clam juice; 1/3 cup water; 1/4 cup heavy cream; 2 teaspoons finely grated fresh lemon zest; 1/4 teaspoon black pepper; 2 tablespoons unsalted butter, softened; 1 shallot, finely chopped; 1 teaspoon salt; 1/2 teaspoon black pepper; 6 (5-ounce) center-cut pieces salmon fillet (preferably wild; 1 inch thick), skin and little bones discarded