Gently with your fingertips mix the flour, salt and finely-diced butter. The texture should become like sand. Tip: As much as possible try to avoid having your skin in contact with the butter - therefore quickly pour the flour around the butter - and avoid mixing too long with your fingers otherwise the butter will melt.
Add the water and the egg yolk. Mix them in, again with your fingertips, until you have a smooth uniform mixture. You can also do this with your mixer (with the leaf utensil).
Knead the dough twice (Put the dough on a floured surface, crush it with the palm of your hand and reshape a ball. This process aerates the dough so it will not shrink in the oven). Cover with plastic wrap and leave it in the refrigerator for at least 1 to 2 hours.
Prepare the tart
Preheat the oven to 160°C (320°F).
Peel the apples, remove the cores and cut them into quarters.
Prepare the caramel. In a pan that can go on your stove or in a pan, place sugar and cubed butter. Melt. When you get a nice caramelized colour, stop the heat (if in a pan, pour in tour tin).
Arrange the apples neatly on the caramel (the round part facing the caramel). You can fill gaps with small pieces of the remaining apples. Number of apples depend on the size of your pan, be sure it is generously garnished with apples.
Take the pie crust out of the refrigerator and leave it at room temperature for a few minutes so that it won't be too cold. Lay it out on a clean, floured surface, roll out the dough with a rolling pin to stretch it to a circle of the correct size (1 cm bigger than you pan).
Put it on top of the apples, with a spatula, tuck the edges of the pastry into the pan, between pan and apples.
Bake for 1 hour at 160°C (320°F).
Unmold right out of the oven. Place a plate on top of the mold, flip and unmold. Doing this when still hot will prevent the caramel from hardening.
If needed, please refer to the conversions and measures article hereMAIN STEPSPrepare the pie pastry, leave it for 1 to 2 hours. Prepare the caramel, add some pieces of butter, followed by the apples (peeled and quartered), stretch the pastry dough, cover the apples and bake.SERVING INFORMATIONThe tarte tatin is normally eaten warm, often served with whipped cream or vanilla ice cream, although purists, such as members of the Brotherhood of Lichonneux of the Tarte Tatin, prefer it unadorned.You can make variations with various fruits (pears, tomatoes ...) and even vegetables (my eggplant and balsamic vinegar Tarte Tatin is a real delight, though I'll wait until next summer, as I like to respect seasons).