Preheat the oven to 400 degrees. Peel, core, and slice the apples into quarters. Set aside.
In your cast iron pan, add the sugar, water, and fish sauce. Make sure the fish sauce coats all of the sugar. Bring that up to a simmer over medium heat. Keep an eye on the caramel so it doesn’t burn. If you notice the caramel changing color more quickly than other areas, give it a swirl, do not disturb it with a spoon or spatula. This should take about five minutes.
Once the caramel is golden yellow, add in the butter and Chinese Five-Spice powder. Once the butter has melted into the caramel, reduce the heat slightly to low. Add in your apples and cook for ten minutes. At first, the caramel may seize up when it’s introduced to the cold, wet apples but over the course of a few minutes, it should thin out as the apples release their juices. Continue to keep an eye on the apples and caramel to make sure the caramel doesn’t burn. Once the apples can be pierced with a fork, set aside to cool.
While the apples and caramel are cooling, lightly roll out your puff pastry dough. Do not roll it out too thinly, we just want to make sure that we have enough space to cut out a 10-inch circular piece.
Rearrange the apples so that the backs are facing the bottom of the pan or on their sides in a circular pattern. Transfer the circular piece of puff pastry to the 9-inch cast iron pan. Tuck the edges of the puff pastry down using a spoon or off set knife.
Bake at 400 degrees for 30-35 minutes or until the top of the puff pastry is golden brown. Allow the tarte tatin to cool for five minutes before placing the serving plate and flipping the tarte. You want the caramel to be loose but not bubbling hot. Serve with a few scoops of residual caramel sauce and vanilla ice cream!
