For the dough: Combine flour, salt, water and egg yolks on the work surface. Knead into a smooth dough, shape into a ball, wrap in plastic and chill for about 30 minutes.
Knead together butter and flour, shape into 6 small rectangular bricks, cover and chill for about 30 minutes.
Place dough on a floured surface and thinly roll out into a rectangle.
Place butter brick in the center of the dough.
Spread butter onto dough, then roll up dough.
Roll out dough into another rectangle. Add a butter brick and spread. Then fold up dough into thirds.
Roll out dough again add a butter brick. Spread brick onto dough, then fold in half twice. Roll out dough again and repeat until all the butter bricks have been incorporated into dough.
Wrap dough in plastic and chill for about 30 minutes.
Roll out dough once move and fold into three parts.
Chill dough overnight, then use as needed or freeze.