Begin by preparing your puff pastry crust with peanut butter.
Locate a plate that is slightly larger in size than the 10-12” cast iron pan or oven-safe skillet that you will be baking with later.
Place the puff pastry crust out on your surface.
Place the plate on the puff pastry crust and use a knife to cut the puff pastry crust in a circular shape by cutting around the edges of the plate.
Remove the excess trimmed puff pastry.
Place ¼ cup peanut butter in microwave safe bowl.
Heat briefly until the peanut butter is warm and more easily spreadable.
Spread a thin layer of the peanut butter in the center of the circle of puff pastry, leaving 1” of exterior of the puff pastry without any peanut butter.
Place the circle of puff pastry in the fridge to allow the peanut butter and crust to cool.
Preheat oven to 375F.
In a saute pan, sprinkle the white granulated sugar evenly over the surface of the pan.
Sprinkle 4 Tbsp water evenly over the top of the sugar.
Turn the heat to medium low, and patiently wait for your sugar to heat up and turn from white to translucent to golden and amber.
This whole process can take roughly 10 minutes.
As the sugar slowly heats, gently swirl the pan (avoid stirring) to encourage even browning.
When large slow bubbles have formed across the surface of the caramel and you have reached the desired amber color, remove the sugar from the heat.
Stir in the 5 Tbsp salted butter and ¼ tsp kosher salt until the butter has melted.
Pour this caramel mixture into the bottom of a well-buttered 10-12” cast iron pan (or stainless-steel oven-proof saute pan with high sides), and distribute caramel evenly across the bottom of the pan.
Prepare your apples by removing the peel, cutting into quarters, and removing the core from each quarter.
Slice these remaining cored apple sections into ¼” slices.
Carefully lay the apples in an overlapping pattern in the saute pan, on top of the caramel.
Continue to lay the layered apple slices until you have filled up the cast iron or saute pan about 80% of the way full.
Avoid overfilling the pan at this stage, as it will leak juices during baking if filled too high.
Remove the peanut butter puff pastry from the fridge.
Carefully invert the puff pastry that has been spread with peanut butter over the top of your apples.
Tuck the excess edges of the puff pastry down between the apples and the pan.
Gently poke holes in the top of the puff pastry with a fork.
Bake at 375F for 20 minutes.
While the tart is baking, gently toast the whole peanuts in a small dry saute pan and remove from heat.
Toss toasted peanuts with 2 tsp white granulated sugar and allow to cool.
Chop peanuts and reserve for use later as garnish.
Lower heat in the oven that is cooking the tart to 350F and continue to bake for an additional 20-30 minutes, or until puff pastry crust is perfectly golden-brown on top.
Remove tart from oven.
Allow to rest at room temperature for roughly 30 minutes.
When the tart has cooled, use a knife to loosen the edges of the tart from the saute pan.
Place a rimmed serving plate that is slightly larger than the saute pan on top of the saute pan, and confidently invert the tarte onto the plate.
Carefully lift the saute pan off the tart.
If any of the apples are stuck to the pan after inverting, remove these and place them back on top of the tart.
Serve with vanilla ice cream and toasted chopped peanuts.