For the fruit:
Heat the oven to 220°C. Slice and stone 4 Flavourburst™ white flesh nectarines and 4 Flavourburst™ yellow flesh nectarines. Combine 3 T melted salted butter with 80 g muscovado sugar, ½ t cinnamon, 1 t vanilla extract and 1 t almond essence. Coat the fruit in the butter mixture, place on a baking tray and roast in the oven for no more than 10 minutes, until the fruit is nice and sticky. Set aside to rest and drain any juices in the pan (to prevent your pie base from going soggy later).
For the meringue:
In the bowl of a stand mixer on low speed, using the whisk attachment, beat 6 egg whites, ⅛ t salt and ½ t cream of tartar until foamy. Increase the speed and slowly add 200 g caster sugar, 1 tablespoon at a time to incorporate evenly, until the meringue is thick and glossy and holds firm peaks.
To assemble the pie:
Take a sheet of readymade puff pastry and cut into a rectangle or to fit your pie dish. Line the edges with a knife to create a border. Prick with a knife, sprinkle with caster sugar and bake at 180°C until golden and puffy, about 15-20 minutes. Add the roasted nectarines, then top with dollops of meringue. Bake in the oven until the meringue turns golden brown, another 15-20 minutes. Slice and enjoy while still warm.