In a medium saucepan, place the orange juice, zest, non diary milk, salt, sugar and cornstarch and whisk really well to combine everything, ensuring there are no lumps of cornstarch.
Place over medium heat and bring up to the boil, whisking often. Once the mixture has boiled, whisk constantly for about 3-5 minutes, until it thickens.
Remove from heat and stir in orange blossom water and the vegan butter. Stir until the butter melts into the the hot mixture.
Pour the mixture into a bowl and cover it with plastic wrap, and then place it into the fridge to cool for an hour or two.
Whip the cream to stiff peaks using a mixer or hand-held mixture.
Carefully fold the orange mixture into the whipped cream, taking care to not deflate the whipped cream too much. Add in most of the chopped chocolate as well, reserving about 1/4 for garnish.
Pour the mixture into the prepared pie shell, and place in the refrigerator to set, an hour or two.
Garnish the finished pie with additional whipped cream and chocolate and serve.