Mille-feuille means “a thousand leaves” and refers to the multiple strata of the classic French puff pastry dough, which is given a greater number of turns (six single turns, preferably over a three-day period) than the more practical, and more commonly used, dough included in this text. It is something of a misnomer to call these pastries by their French name when using this puff pastry recipe, as the dough falls short of 1000 layers. A way to make up for it is to take finished puff pastry made according to the directions in this book and give the dough a half-turn; roll out the dough as you would to make a double turn, then fold it in half. The dough will then have just over 1000 layers. However, if you are not such a stickler for accuracy, don’t worry.
This version of napoleons, like the one that precedes it, contains three strips of puff pastry. Because of this, you may want to increase the cornstarch in the pastry cream by 1ounce (30g) per full recipe. The firmer pastry cream will make it easier to slice and handle the assembled napoleons.