Preheat the oven to 350°F (175°C). In a mixing bowl, combine flour, butter, and powdered sugar until crumbly. Add egg yolk and mix until dough forms.

Press the dough into the tart pan and prick the bottom with a fork. Bake for 15 minutes or until golden. Let cool.

In a saucepan, combine mango puree, sugar, lime juice, and egg yolks. Cook over medium heat, stirring constantly until thickened.

Remove from heat and stir in butter until melted and smooth. Let cool slightly.

Pour the mango curd into the cooled tart crust and spread evenly. Chill in the refrigerator for at least 2 hours before serving.