Sweet Orange Buns

Name: Sweet Orange Buns
Ingredients: 1 1/4 cups milk, heated to 115°; 1 (1/4-oz.) package active dry yeast; 1/3 cup sugar; 2 tablespoons unsalted butter, melted, plus 16 tablespoons, softened; 1 1/2 teaspoons kosher salt; 1 large egg, lightly beaten; 4 cups flour; 1/2 cup packed light brown sugar; 1/3 cup orange zest (from about 4 oranges); 3 cups confectioners’ sugar; 1 teaspoon orange extract (not optional); 1 teaspoon vanilla extract; 1 tablespoon fresh orange juice