For the layers, roll out the pasta sfogliata on a floured surface into a
While the layers are chilling, prepare the pastry cream: bring the milk, lemon zest, and half the sugar to a boil in a nonreactive saucepan. While the milk is coming to a boil, whisk the egg yolks in a bowl and whisk in the remaining sugar. Sift the flour over the yolk mixture and whisk it in. Whisk one-third of the boiling milk into the yolk mixture. Return the remaining milk to a boil, and, beginning to whisk the milk first, pour in the yolk mixture, whisking constantly until the cream thickens and boils. Boil, whisking, 1 minute. Whisk in the vanilla.
Pour the pastry cream into a clean bowl, press plastic wrap against the surface, and chill.
Remove the baked puff pastry layers to a cutting board and cut each layer into a
For the apricot filling, combine the preserves and rum in a saucepan and bring to a boil over medium heat, stirring often. Strain the mixture into another pan, return to low heat, and reduce until sticky, about 5 minutes, according to the original density of the preserves.
To assemble the mille foglie, place one of the puff pastry squares on a
Smooth the sides with any filling that oozes out, using a thin metal spatula, and press the reserved crumbs against the sides with the palm of your hand.
Dust the top of the mille foglie generously with the confectioners’ sugar and keep in a cool place for no more than 3 or 4 hours before serving.
For advance preparation, make all the component parts early in the day but only assemble a few hours before serving.
Use a sharp, serrated knife to cut the mille foglie into rectangles or squares for serving.
Confectioners’ sugar for finishing
© 1990 Nick Malgieri. All rights reserved.