Got It! Two tries!!
The layers are very, very, thin.
I baked them with a temperature of 180 deg for abt 8 mins with top and bottom heat, turn down to 140 deg for another 8 mins with only bottom heat on. Having the top of the biscuits covered at all times and at the bottom layer, a piece of parchment paper in the tray. I had two trays at the bottom to prevent the biscuit being burnt.
Turn of the oven. Do not remove the biscuits until abt 20-30 mins later. With the top still covered with another parchment sheet.
The skin : Much, much thinner than those bought from the stores.
The chinese pastry is much easier than the western pastry skin. But you can have sweet or savoury fillings.
The same pastry is also made into mooncakes, curry puffs and many others.