How can you achieve the glazed top in a mille-feuille?
The dessert discribed is not truley a "Tom Pouce", that is a different pastry.  What is discribed in the question is a "Napoleon" dessert pastry.  The Mille Feuille or Puff Pastry is topped with an icing called "Fondant".  Fondant in it's simplest (shortcut) form is made by mixed powdered sugar and water until the desired thickness is reached.  Some time in the open air will harden it a little further beacause of the water drying out.  Fondant made correctly is by making a simple syrup (water and sugar cooked together), cooking it to the "soft ball" stage or temperature of simple syrup, then dispursing it onto a marble slab (to cool it quickly) and with 2 baker knives (one in each hand) fold and kneed the sugar until it frosts from transluscent color to the frosty and shyny white color.  This is an old skill which has been taken over by machines.  Fontdant is now purchased from larger makers in 5 gal. buckets for a cost of appr. $25.00.