In a large bowl, combine the flour, baking powder and salt; cut in cream cheese and butter until crumbly. Gradually add water, tossing with a fork until dough is moistened. Knead in bowl until a ball forms; flatten into a disk. Wrap in plastic; refrigerate for at least 1 hour or until easy to handle.
In a small bowl, combine the mangoes, jelly, mint and lemon zest; set aside. In a small bowl, whisk egg and water.
On a floured surface, roll out dough to 1/8-in. thickness; cut into 4-in. circles. Spoon 2 teaspoons mango mixture into the center of each circle. Brush edges with water; fold dough over filling and seal with a fork. Brush with egg mixture; sprinkle with sugar.
Place on foil-lined baking sheets. Bake at 375° for 20-23 minutes or until golden brown. Remove to wire racks to cool.