Add the pie crust mix and ¼ cup of water to a large bowl, then mix with a fork to combine.
Separate the mixture into 2, and roll ½ of the dough into a ball.
Place it on a floured work surface, and roll the crust out into a thin layer the size of a pie pan.
Carefully transfer the dough to a pie pan, and press it down.
Using a knife, remove the excess edges.
Using a fork, poke the bottom of the crust several times.
Bake the pie crust for 10 minutes, then remove it from the oven, and allow it to cool.
In a small bowl, add the remaining water and the contents of the gelatin envelope. Mix to combine, and allow the gelatin to sit untouched for 5 minutes.
Meanwhile, in a small saucepan, add the sugar, flour, salt, and milk, and whisk to combine.
Bring the contents of the saucepan to a boil, and cook for 1 minute.
Remove the saucepan from the heat, and mix in the vanilla extract and the gelatin mixture.
Set the pan in an ice bath to cool quickly.
Add the heavy cream to the bowl of a stand mixer, and whisk it for about 3 minutes until stiff peaks form.
Gently fold the whipped cream into the milk mixture.
Pour the cream filling into the baked crust, spreading it out evenly.
Sprinkle shredded coconut evenly on top.
Chill the pie in the fridge for at least 4 hours, then serve.