01 - Blend flour, powdered sugar, and salt in a food processor. Add cold butter and pulse until mixture resembles coarse crumbs. Add egg yolk and 1 tablespoon cold water, pulsing until dough just comes together. Add additional water only if necessary. Flatten dough into a disk, wrap in plastic, and refrigerate for 1 hour.
02 - Roll chilled dough on lightly floured surface to fit 9-inch tart pan. Press dough into pan and trim edges. Prick base with fork. Chill for 15 minutes. Preheat oven to 350°F. Line shell with parchment and fill with baking weights. Bake for 15 minutes, remove weights and paper, then bake 10 more minutes until golden. Cool completely.
03 - Whisk mango puree, eggs, egg yolks, sugar, and lime juice in saucepan. Cook over medium-low heat, stirring constantly until thickened and mixture coats back of spoon, about 10 minutes. Remove from heat. Stir in butter cubes until melted and smooth. Strain through fine mesh sieve for silky texture.
04 - Pour mango curd into cooled tart shell, smoothing top with offset spatula. Refrigerate for at least 1.5 hours until completely set.
05 - Arrange fresh mango slices, toasted coconut flakes, and mint leaves on top before serving. Slice and serve chilled.