Make the dough by mixing together all the wet ingredients. Integrate the flour, bit by bit. Add the salt. Form a dough, then wrap it in clingfilm and put it in the fridge.
Leave the dough to rest in the fridge for 12 hours, or overnight.
Grate the apples on the large section of the grater and put them in a pan.
Add 6 tablespoons of sugar and mix together until the liquid that forms in the pan reduces.
Turn the heat off and let it cool down completely.
Preheat the oven to 180 degrees Celsius or gas mark 4.
Divide the dough into two equal parts and roll them out.
Cover a baking pan with baking paper, and put the first dough at the bottom, making sure to cover the edges as well. Sprinkle a little bit of semolina over the dough, to help absorb the moisture and avoid a soggy bottom.
Put the apple filling inside and sprinkle the cinnamon on top. Sprinkle a bit more semolina on top. Add the second layer of dough, and prick it with a fork.
Bake for one hour, or until the pie lid starts to brown.
Decorate with icing sugar and let it cool down completely before cutting it into squares.