Mix flour, salt, butter chunks, and ice cold water in a bowl, leaving butter chunks whole.
Shape into a rough rectangle, cover, and chill for at least an hour.
Roll it out long.
Perform a bookmaker fold: bring both ends into the centre, then fold in half like a book.
Chill for 30 minutes.
Repeat the roll, fold, and rest process three times.
Final roll and trim the edges.
