*caster sugar is an extra fine sugar great for making caramel. If you can’t find this, look for labels "superfine" or "baker’s sugar."
Preheat oven to 350F.
Cut your apple into quarters and remove the core. Slice into thin pieces and set aside.
Take an 8-inch baking tin and place it on the stove top. Melt your butter on medium heat and slowly stir in your sugar until it's fully dissolved. Stir occasionally for roughly 5 minutes until it's a pale golden brown. Remove from heat and place your apples in the caramel (it’s wicked hot, so be careful). Create a pinwheel pattern, or just throw those babies in there! Totally up to you. Do a nice dusting of cinnamon on top of the apples. Don’t be shy.
Meanwhile, flour a flat surface and roll out your pastry dough. If you don’t have a rolling pin, a tall glass will do the trick. Roll your dough into a circle larger than your pan (at least an inch hanging off the side).
Place the dough on top of the apples and tuck all the excess dough into the sides until it’s even. Stab a few ventilation holes on top and pop it in the oven. Cook for 30 minutes.
Take your serving plate or tray and place it facedown on top the pan. Using two oven mitts, hold the sides of the pan and plate and do a quick flip. Lightly remove the pan, and voila! Tarte Tatin!
Some people like to serve this with ice cream or creme fraiche but I’m a purest ... just dig in.