Mix flour, butter, water, egg, and salt until you get a smooth ball
Flatten into a disk, wrap in plastic, and rest in the fridge for at least 1 hour (overnight is best)
Heat apple quarters in a pan for 10 minutes to remove moisture
Heat sugar gradually until it reaches 180°C and develops a golden amber color
Remove from heat and wait 5 minutes before whisking in the butter
Add a pinch of salt to the caramel
Pour caramel into your mold and arrange apples on top
Cover with rolled-out dough and cut a small hole in the dough to let steam escape
Bake at 190°C for 20-25 minutes
Flip immediately and serve
