In a large bowl add the flour and butter then rub together until they look like cracker crumbs up to the size of a pea.
Sprinkle the ice water over the flour and butter then stir lightly together with a butter knife.Tip: If you squeeze a handful of the dough in your hand and it holds together it is good, if it doesn’t slowly add a little more ice water.
Divide the dough in half and make it into two chubby dough disks. Chill until needed but at least an hour.
Apple Filling
Clean the apples the half and remove the core. Slice thinly into even pieces.
In a bowl add the sugar and mix well. Set aside until needed.
To Assemble
Roll one of the discs out to a round circle about 14 inches (35 cm) round. Place on a baking tray.
Place half the apples in the center spreading slightly. Fold up the edges of the pastry overlapping yet leaving the center apple exposed. Chill for 30 minutes.⅔
Preheat the oven to 425 degrees F (220 degrees C).
Whisk the egg white and water together, then brush on the exposed areas of the pastry. Sprinkle these areas with sugar.
Place the Apple tart in the oven and bake for 10 minutes, then reduce the temperature to 375 degrees F (190 degrees C) and bake for an additional 30 minutes, until golden brown.
Remove the tart from the baking tray and place it on a cooling rack. Serve warm or cold.