Preheat the oven to 350F. Place the graham crackers into a food processor and blend to crumbs. Add the coconut, sugar, and salt. Blend until combined.
Add the melted butter and pulse until just combined. (If you don't have a food processor, you can just crush the graham crackers into crumbs then combine all the ingredients in a bowl)
Transfer the mixture to an 8-inch round baking dish. Press the crumbs along the edges of the dish and then flat on the bottom. Transfer to the oven and bake for 10 minutes. Set aside to cool.
While the crust cools, make the filling: add the heavy cream and sugar to a large pot over medium heat. Stir as the mixture comes to a boil, the continue to stir while it boils for 5 minutes. After 5 minutes, turn off the heat and add the passionfruit juice and vanilla extract and stir to combine. The mixture should thicken slightly.
Carefully pour the hot liquid into the crust. Cover with plastic wrap and transfer to the fridge to cool completely, until the liquid has set, about 2 hours.
To make the whipped cream topping, add the heavy cream, sugar, and vanilla extract to a large bowl. Use a stand mixer, hand mixer, or whisk to mix until soft peaks form (4-10 minutes, depending on what method you're using).
Transfer the whipped cream to the top of the tart and shape how you desire. Keep the tart in the fridge until you're ready to serve and enjoy!