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. Add more water if necessary. Flatten dough into a disk, wrap in plastic, 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, trim edges, and prick base with fork. Chill shell for 15 minutes. Preheat oven to 350°F. Line tart shell with parchment paper and fill with baking weights. Bake for 15 minutes, remove weights and paper, then bake another 10 minutes until golden. Let cool completely.
03 - Whisk together mango puree, whole eggs, egg yolks, sugar, and lime juice in a saucepan. Cook over medium-low heat, stirring constantly until thickened, about 10 minutes. Mixture should coat the back of a spoon. Remove from heat and stir in butter cubes until smooth. Pass curd through a fine mesh sieve for silky texture.
04 - Pour cooled mango curd into the baked tart shell, smoothing the top with an offset spatula. Refrigerate for at least 1.5 hours until completely set and firm.
05 - Arrange fresh mango slices, toasted coconut flakes, and mint leaves on top just before serving. Serve chilled with whipped cream or coconut sorbet if desired.