Preheat the oven to 400°F. Wash and peel the apples. Cut them into quarters, removing the core.
Add half the butter and half the sugar to a pan on medium heat. Mix and let it melt.
Optional: Cut the vanilla bean in half lengthwise. Remove the inside using a knife.
Once the caramel starts to darken, add the vanilla (optional) and the apples. Mix and cook for 15 minutes on low heat. Stir occasionally.
In the meantime, mix the flour, the rest of the butter (softened), the sugar, and salt in a bowl.
Mix until the dough forms a crumbly texture. Add the yolk and 3 tablespoons of water. Combine well and form the dough into a ball.
Flour your work surface and roll out the dough to 1/4 inch thickness.
Check the apples: they should be lightly browned on the outside and slightly translucent.
Optional: put the vanilla bean at the base of the cake pan.
Pour the apples and the caramel into the cake pan. Arrange them with the thick part facing down.
Top with the dough and fold in the borders. Prick a few times with a fork and bake for 20 minutes at 400°F.
Remove from the oven and let cool for 5 minutes.
Place a large plate over the cake pan, hold it in place and quickly flip. Remove the cake pan. Enjoy!
Average estimated amount for one serving