Sticky Toffee Pudding with Port Toffee Sauce

Name: Sticky Toffee Pudding with Port Toffee Sauce
Ingredients: For the pudding:; 5 tablespoons unsalted butter, melted; 8 ounces (about 1 1/4 cups) pitted prunes, quartered; 1 cup tawny port; 2 teaspoons pure vanilla extract; 1 1/4 cup all-purpose flour; 1/2 teaspoon baking powder; 1/2 teaspoon baking soda; 1/2 teaspoon salt; 3/4 cup packed dark brown sugar; 1/2 teaspoon finely grated lemon zest; 2 large eggs, at room temperature; For the port toffee sauce:; 8 tablespoons unsalted butter; 2/3 cup heavy cream; 3 tablespoons tawny port; 2 tablespoons mild molasses; 1 teaspoon lemon juice; 1/8 teaspoon salt; 1/2 cup chopped roasted and salted pistachios (optional); Maldon salt (optional)