01 - Blend flour, powdered sugar, and salt in a food processor. Add cold cubed butter and pulse until mixture resembles coarse breadcrumbs. Add egg yolk and 1 tablespoon cold water, pulsing until dough just comes together, adding more water if necessary. Flatten into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour.
02 - Roll out chilled dough on a lightly floured surface to fit a 9-inch tart pan. Press dough into pan, pressing up the sides, and trim excess dough from edges. Prick the bottom all over with a fork. Return shell to refrigerator for 15 minutes. Preheat oven to 350°F.
03 - Line chilled tart shell with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes, then carefully remove weights and parchment. Continue baking for another 10 minutes until crust is golden brown. Allow to cool completely before filling.
04 - Whisk together mango puree, whole eggs, egg yolks, sugar, and lime juice in a saucepan. Place over medium-low heat, stirring constantly with a heat-proof spatula, until mixture thickens enough to coat the back of a spoon, about 10 minutes. Remove from heat immediately.
05 - Stir butter cubes into hot curd one piece at a time until fully incorporated and smooth. For an extra silky texture, pass curd through a fine-mesh sieve into a clean bowl. Allow curd to cool slightly.
06 - Pour mango curd into cooled tart shell, spreading evenly with an offset spatula. Refrigerate for at least 1.5 hours or until curd is completely set. The tart can be made one day ahead and stored covered in the refrigerator.
07 - Arrange fresh mango slices, toasted coconut flakes, and mint leaves on top of set curd just before serving. Serve with whipped cream or coconut sorbet if desired. Slice and serve chilled.