In a small bowl, bloom the gelatin by sprinkling it over 1/4 cup water. Let sit for 5–10 minutes.

Prepare an ice bath large enough to fit your saucepan and set aside.

In a large saucepan, whisk together 1/3 cup sugar, flour, salt, and milk. Cook over medium heat, stirring constantly, until the mixture boils. Boil for 1 minute, then remove from heat.

Whisk the bloomed gelatin into the hot milk mixture. Stir in vanilla and almond extracts. Place the saucepan into the ice bath to cool rapidly.

In a bowl, beat 1/2 cup heavy cream until stiff peaks form. Set aside.

In another bowl, beat egg whites with cream of tartar and remaining 1/3 cup sugar until stiff peaks form. Set aside.

Transfer the cooled milk mixture to a large mixing bowl. Use an electric mixer to beat until smooth. Gently fold in the whipped cream, beaten egg whites, and shredded coconut until just combined.

Spoon the filling into the premade graham cracker crust and smooth the top.

Whip the remaining 2 cups of heavy cream to stiff peaks and pipe or spread over the top of the pie.

Refrigerate for at least 1 hour before serving. Keep chilled.