Combine 1 ½ cups crumbs, ¼ cup coconut, 2 tbsp sugar, and a pinch of salt. Stir in 5 tbsp melted butter. Press firmly into a 9-inch tart pan and bake at 350°F for 10–12 minutes until dark gold. Let cool completely.
Puree fresh mango in a blender, then pass it through a fine-mesh sieve to remove all fibers. Measure out 1 ¼ cups of the silky puree.
Whisk the purée, 6 egg yolks, ½ cup sugar, and ¼ cup lime juice in a heavy saucepan over medium-low heat. Whisk constantly for 8–10 minutes until the mixture is thick enough to coat the back of a spoon. Do not boil.
Remove from heat. Stir in lime zest and salt. Whisk in 6 tbsp cold, cubed butter two pieces at a time, waiting for each to melt before adding more. This creates a stable, silky emulsion.
Pour the curd into the cooled crust. Press plastic wrap directly onto the surface of the curd to prevent a rubbery skin from forming.
Refrigerate for at least 4 hours (ideally overnight). Remove the tart ring and garnish with fresh mango or mint just before serving.