98grams(7tbsp)unsalted buttervery cold and cut into small cubes
Preheat the oven to 375 ºF.
Peel all the apples. Slice them in half and remove the cores with a pairing knife. You can place the cut fruit in a big bowl of water with a squeeze of lemon to prevent them from going brown.
Butter a 10-inch cast-iron skillet or stainless steel Rondeau pot.
Place in on the burner. Sprinkle with one quarter of the sugar and tilt and swirl the pan to evenly distribute the sugar in an even layer.
Heat the pan on medium–high, swirling the pan to melt the sugar evenly. When it's almost all melted, add a little more.
Continue swirling and tilting the pan until all the sugar is in the pan and melted.
Heat the mixture until the sugar has caramelized and is a deep amber colour.
Take the pan off the heat and carefully add the butter, swirling the pan to mix it in.
Add the vanilla bean paste and the salt and swirl the pan to mix it in.
Arrange the apple halves, cut-side up so that the rounded side is down. It's okay if they overlap a little. You can always rearrange them later.
Bake the apples for 15 minutes in the preheated oven.
When the apples are par-baked, remove the pan from the oven. At this point, because the apples are softer, you can carefully rearrange the apples to fit them tighter. Set aside.
Increase the oven temperature to 400 ºF.
Roll out the puff pastry (or homemade pie crust) and trim it to make an 11-inch circle (you can use a plate or a pot lid as a template to cut a circle). Prick the pastry with a fork. Carefully place the disk of rolled pastry overtop the baked apples.
Return the pot to the oven and bake the tarte tatin for about 45 minutes or until the pastry is golden brown all over. The filling should be bubbling underneath (you will hear it).
Take the pot out of the oven and set it to cool for 10 minutes on a wire rack.
Run a knife around the edge of the tart to make sure it's loose. Place a large serving plate over the pot and carefully flip the pot/tart onto the plate. Lift the pot off the tart and rearrange any fallen apples.
Serve warm with vanilla ice cream.
Homemade pie crust
In a large bowl, using a fork, whisk together the flour and the salt.
Drop in the cubes of cold butter. Using your palms and your finger tips, work the butter into the flour until you get a coarse mixture, like wet sand.
Add the cold water and stir it in with a fork.
Using your hands, work the dough until it comes together, then pat into a disk, wrap in plastic wrap, and chill at least 30 minutes before using it.
The type of skillet you use may have an impact on the baking time. I used a stainless steel Rondeau pan from Le Creuset.