Make coconut crust. Preheat the oven to 350°F/175°C. Grease an 8-inch tart pan and set aside.
Process flour, sugar, shredded coconut and salt in a food processor for a few seconds until combined. Add butter and pulse until the dough is no longer dry and starts to clump together. This process would take around 15 seconds. Remove from food processor and turn dough to a lightly floured surface and form into a ball. Use your hands to press the dough firmly onto the bottom and sides of the tart pan, spreading evenly to the edges. Trim the edges of the pastry to fit the tart pan if needed.
Use a fork to poke 6-10 holes into the dough then fill with pie weights or dried beans or rice, making sure they’re evenly distributed over the surface. Bake for 10 minutes then remove from the oven, let it cool.
Make the filling. In a large bowl, whisk all the ingredients except flour until combined. Add in flour and whisk until no lumps remaining.
Pour the mixture into the baked crust and bake for 18-20 minutes until the filling is set.
Remove from the oven and chill in the fridge for at least 4 hours.
Top the tart with powdered sugar. Store the tart in the fridge for up to 5 days.