Mille Foglie - cooking recipe

Ingredients

1 sheet puff pastry, thawed
2 tablespoons all-purpose flour
1/4 teaspoon salt
2/3 cup granulated sugar
2 tablespoons cornstarch
4 large egg yolks, room temperature
2 cups whole milk
2 teaspoons vanilla extract
2 tablespoons unsalted butter, diced

Preparation

Oven 425 or 450 (I use 450).
for the puff pastry - place between 2 sheet pans with a piece of parchment paper above and below the pastry (you want to stack the sheet pans on top of each other).
Bake for 10 minutes - if pastry isn't crisp and golden brown - remove top sheet pan and parchment and bake about 1-2 minutes longer.
cool on wire rack.
for the pastry cream - Whisk together the flour, salt, sugar, and cornstarch, in a non-reactive saucepan.
In a mixing bowl, whisk the milk into the yolks.
then whisk them into the sugar-starch mixture. Whisk well to be sure all the cornstarch and flour is picked up off the pan bottom and dissolved.
Set the pan over medium heat and cook the custard mixture for about 12 minutes, until it thickens and comes to a boil (Stir with a wooden spoon on and off for the first 5 minutes, then stir constantly for about 7 minutes longer) until the mixture really thickens and reaches a boil, and you see fat heavy bubbles work up to the surface and burst between stirs.
Occasionally use a whisk instead of the spoon to break up and remove any lumps.
Then boil for 1 full minute (count to 60) while stirring constantly, covering the entire bottom of the pan with the spoon. Remove the pan from the heat.
The cream is sufficiently cooked if it is smooth and thick and will generously coat the spoon--it should hold a clearly defined line when you draw your fingertip through the cream clinging to the back of the spoon.
If you suspect that the cream may be lumpy, pass it through a strainer set over a bowl.
Stir in the butter and the vanilla extract, if using.
Spoon the cream into a bowl. To prevent a skin from forming, press a piece of buttered plastic wrap onto the surface, or dab it with butter or sift on a very light coating of confectioners' sugar.
Cool, then cover and refrigerate (the cream should be cool enough to use after about 20 minutes).
Cut the puff pastry in half, place 1 half on the bottom of a pyrex (I use 9x13, but it will be smaller)
Spread the cream over the pastry, and top with remaining half.
Sift powdered sugar over all, and chill till ready to serve (about 1 to 2 hours is best).
Cut with a serrated knife.
You can double this by doubling the cream (make 2 separate batches - it's easier) and using 2 sheets of pastry - you will have to trim the pastry to fit into a 9x13 pan on the sides.