Place a sheet of baking parchment on your baking sheet and sprinkle with brown sugar, then place a few pieces of butter on top.
Drain your apple slices.
Arrange your puff pastry on the butter pieces.
Place the apple slices in a rosette on the puff pastry.
Sprinkle with brown sugar again, place a piece of butter and a little cinnamon on top of your rosette.
20 minutes in the oven at 200 degrees and cool on the rack.
Enjoy lukewarm!