My mother, Maureen, makes a stack of apple tarts every September and gives them away to friends and family. They've so many apples on their tree so this is a great way to use them up. The tart also freezes well.
Pastry: Sift the flour and salt into a large mixing bowl. Add the diced butter and use your fingers to rub the butter pieces into the flour. Keep doing this until they look like sand particles. Sprinkle over the sugar and mix in.
Add 3 tablespoons of cold water and mix again. Add a few drops more water if the dough doesn't come together. With your hands, form it into a dough, handling as little as possible. Wrap the dough in plastic wrap and chill for half an hour before rolling out.
Preheat oven to 180 degrees C. Lightly grease a 20cm pie tin or pastry dish.
To Assemble: Slice pastry dough in half, roll out into 2 circles, lining the tin with one. Place apple slices in the pastry base. Sprinkle over sugar, then top the pie with the other pastry circle. Trim edges of pastry with a sharp knife and crimp to seal.
Brush with a little egg and sprinkle with caster sugar (optional). Cut an 'X' in the top to let out some steam while baking.