Peel, empty, and cut the apples into quarters (or smaller if desired). Bear in mind these will shrink during baking.
Preheat the oven to 160°C
In a pan, heat the water and sugar until you get a caramel colouring.
Take the pan off the heat and add the butter little by little, mix in until the butter is fully melted.
Pour the caramel into the cake tray and let cool
Put the apples in tightly, they should exceed the pot size
Cook in oven for 1.5 hours, then remove and allow to cool
Place the puff pastry on top of the apples and press down on the sides to wrap, ensuring apples are covered in caramel.
Increase oven temperature to 170°C and cook for another 35 minutes
Allow tart to cool in fridge for minimum 2 hours
Empty tray upside down onto a plate and serve with plain yoghurt, cream, or vanilla ice cream