Mille-Feuille

To make the cream filling

Step 1

In a medium bowl, vigorously whisk together the egg yolks and sugar until lightened. Whisk in the cornstarch. In a saucepan, warm the milk and the vanilla seeds and pod. Slowly pour the milk mixture into the egg mixture while whisking constantly. Pour the entire mixture back into the saucepan and cook over medium heat, whisking constantly, until very thick, about 5 minutes. Discard the pod.

Step 2

Soak the gelatin sheets for 10 minutes in a bowl of cold water. (If using powdered gelatin, sprinkle it over ¼ cup plus 2½ Tbsp. cold water and stir to moisten it; let soften for 5 minutes.) Squeeze the water from the gelatin sheets and add them to the warm water; stir to dissolve. Stir the gelatin into the warm custard (or stir in the softened powdered gelatin, if using, until fully melted). Let cool slightly. Add the butter pieces to the custard. Using an immersion blender, blend the mixture until smooth and the butter is incorporated. Cover the surface with plastic wrap and refrigerate until cooled.

To make the Mille-Feuille

Step 3

Whip the cream, then fold it into the cooled custard mixture using a silicone spatula or whisk. Cover the surface with plastic wrap and refrigerate for at least 2 hours.

Step 4

Bake the puff pastry. Preheat the oven to 350°F. Line a baking sheet with parchment paper. Roll out the puff pastry dough ⅛-inch thick into a rectangle that will fit on your baking sheet. Transfer the dough to the baking sheet, then place a piece of parchment paper on top to cover it. Place a second baking sheet on top to prevent puffing during baking. Bake for 30 minutes. Cool completely.

Step 5

Depending on the size of your serving plate, carefully cut the pastry into three squares, rectangles, or circles of equal size (you can cut out a cardboard template as a guide).

Step 6

Sift a layer of confectioners’ sugar on top of one of the layers and bake it for 5 minutes at 450°F, watching it carefully so that it caramelizes but does not burn.

Step 7

Assemble the mille-feuille. Scrape the cream into a pastry bag fitted with an open star pastry tube.

Step 8

Pipe a layer of cream rosettes on top of one of the non-caramelized layers.

Step 9

Cover the rosettes with one of the puff pastry layers and pipe a second layer of cream rosettes.

Step 10

Place the caramelized puff pastry layer on top.

Step 11

Place parallel strips of paper on top at a diagonal and dust with confectioners’ sugar.

Step 12

Carefully lift off the strips to reveal the striped pattern.

Step 13

Pipe one or two rosettes on top for decoration (optional).