Preheat oven to 350degrees. In a large bowl, cream butter and sugar until light and fluffy. Beat in eggs, orange zest and vanilla. In a small bowl, whisk flour, baking powder and salt; gradually beat into creamed mixture. Stir in coconut, mangoes and pistachios., Divide dough in half. On ungreased baking sheets, shape each half into a 12x4-in. rectangle. Bake 15-20 minutes or until firm to the touch., Cool on pans on wire racks until cool enough to handle. Transfer baked rectangles to a cutting board. Using a serrated knife, cut crosswise into 1/2-in. slices. Place on ungreased baking sheets, cut side down. Bake 6-7 minutes longer or until golden brown. Remove from pans to wire racks to cool.,