Peel the apples and cut them into four to eight pieces.
Trim the tips and set them aside.
Thoroughly coat the bottom and sides of a copper pan or baking mould with softened butter, then sprinkle with sugar.
Press the apple pieces into the butter and sugar, placing them rounded side down.
Fill any gaps with the apple tips.
Build up a second and third layer of apple, slightly overfilling the pan or mould.
Place the pan or mould over an even heat, allowing the sugar to caramelise slightly.
Let the caramelised apples stand for eight hours to soak up the caramel, fully saturating them.
Roll out a slice of puff pastry to 3 mm thickness and prick it with a fork.
Cover the apples with the pastry, tucking the sides around the apple layers.
Bake at 180°C for 15 to 18 minutes.
Allow to cool, then reheat to lukewarm before serving.