Peal and core all the apples. Slice in half from the top to bottom (not around the circumference). Slice in half again. I find quarters are easier to fit more in the pan.
Melt the butter in an 8-10 inch skillet. You can make this same recipe in a 12 inch skillet but add at least one more apple.
Arrange apples with the outside (round part) facing down into the pan. Make sure to crowd them to cover the whole bottom. As they cook they will shrink and you don’t want to find yourself with bare spots!
Pour sugar over the top of the apples in the pan along with the pinch of kosher salt and pinch of cinnamon if desired. On medium heat allow the sugar to caramelize, swirling if needed, and rotating the pan to make sure the caramel is even all the way around. Take the caramel to a medium amber.
Flambée! Add the alcohol on top of the caramelized apples. Light on fire using a gas burner, kitchen torch or lighter. Allow the alcohol to burn off completely (no flame, no more alcohol).
Remove from heat and allow to cool to room temperature.
Preheat oven to 375°F
Cut puff to be just slightly larger than your pan. Place on top of apples, rolling in the sides if they are slightly too large.
Bake in preheated oven 20-30 minutes or until the puff pastry is puffed and golden brown.
Allow to cool about 10 minutes in the pan before carefully flipping it onto a large plate or serving dish. I find it easier to cut pretty slices when it is hot, so I usually cut mine ahead of time with a sharp knife.