Heat the oven to 220°C. You will need a 28cm Tart Tartin pan, ideally Mauviel as we've used here.
Cut the butter into thin slices and arrange on the base of the tin to cover completely. Carefully sprinkle over the sugar in an even layer. Peel, halve and core the apples and arrange in the tin, packing as tightly as you can.
Place the tin on the stovetop over medium-low heat. Cook and bubble away until the butter and sugar have turned into a rich, dark caramel, 20-30 minutes. Keep an eye out to prevent burning.
Lightly flour your bench. Lightly roll the pastry into a round to fit the top of the tin. Using the rolling pin to help you, lift the pastry and place on top of the apples. Tuck the edges of the pastry inside the tin, then prick pastry with a fork.
Place the tin on a shallow baking tray and place in the oven. Cook for 20-30 minutes until the pastry is well browned and crisp.
Remove from the oven and leave to cool for about 5 minutes. Run a round-bladed knife around the inside of the tin to loosen the edges of the pastry.
Place the porcelain serving platter over the tin and invert to turn out the tart.
Serve warm with vanilla whipped cream.