Preheat the oven to 200°C.
Cut the apple into thin slices. Soak the cut apples in salt water to avoid browning.
Cut a circle out of the puff pastry sheet, it should be slightly bigger than the apple.
Layer the apples nicely at the centre of the puff pastry.
Sprinkle some sugar on top.
Put in the oven for 20-25mins, until the top turns a bit brown.
Brush a thin layer of maple syrup on top to give the shiny glossy look.