Preheat your oven to 375 degrees.
Peel, remove cores and quarter apples and add to a large bowl. Sprinkle the juice of the lemon over all of the apple slices and toss them to make sure they are coated. This will help them from turning brown.
In a large nonstick skillet over medium heat, add sugar and cook until nice and smooth and a nice amber color. Make sure to stir constantly. Stir in butter then Baileys and melt together completely then add the apple quarters, ensuring that they are coated with the caramel sauce.
Cook for about 15-20 minutes while continuing to baste the apples and turn them in the caramel. Once caramel has mostly reduced, remove from heat.
While apples cook, work on puff pastry. Using a 9 inch round cake pan, trace and cut a circle out from your sheet of puff pastry a little bigger than the edge of the pan.
Transfer the apple slices to a 9 inch cast iron skillet or 9 inch baking pan that has been LIBERALLY non stick sprayed or greased and place in a decorated design to the bottom of a pan. Pour remaining caramel on top of those apples.
Next carefully place the puff pastry circle on top of the apples and tuck the sides down into the pan. Poke fork holes on top.
Bake for 45-50 minutes or until the pastry is golden brown and no longer soft. It should be pretty firm.
Cool for about 10 minutes, go along the sides and then then invert onto a serving plate.