Prepare the sugar syrup by adding 1 tablespoon of hot water to the sugar and whisk until the sugar dissolves and then stir in the cinnamon. Keep aside.
Roll out your puff pastry and cut it to the size of your tart tin. Lightly grease the tart tin and line it with the cut pastry. Make fork indents down the middle of the tart. Place the leftover pastry back in the fridge.
Fill the tart with ceramic beans or any dried lentils and blind bake the tart for 20 mins. Remove and allow to cool.
Fill the tart with the pistachio cream creating an even layer.
Slice the apples thinly and evenly into half moons and then fan out and carefully using a spatula place on top of the pistachio cream, repeat for all the apples, alternating the colours and filling in any gaps.
Coat the apple slices and the pastry edge with the sugar syrup and bake for 20 mins at 180 °C (356 ℉) or until the tart is golden. Remove and allow to cool.