The Perfect Mille-Feuille: Secrets of French Pastry Revealed!

Instructions :
Preparation of the dough:
Make a well with the flour and salt.
Pour some of the very cold water into the center and dissolve the salt.
Gradually incorporate the flour towards the center.
Add the rest of the water then the butter.
Do not overwork the dough, cover with cling film and refrigerate for 30 minutes.