mixing bowl with paddle mix both flours, sugar and 550 gr. butter.
Mix until crumbly.
Put on sheet pan and bake at 300F until golden brown.
When cool grind in
a food processor and grind.
Put back in mixer with paddle and add the rest of the butter.
Mix until crumbly again. Remove from mixer
and place between two sheets of parchment paper.
Roll it down to 2-½ mm and keep in freezer to use as needed.
Bake at 300F
for about 15 minutes and cut whilst still warm.
Put back in freezer to cool before attempting to pick it up.