Mille-Feuille (Napoleon)

Before you start

Mille-feuille means "a thousand leaves," and the name describes the many fine layers of puff pastry, not the number of sheets on the plate. The classic dessert stacks three thin sheets of baked pastry with two layers of vanilla pastry cream. The pastry is baked under a weight so it rises only a little and becomes dense, crisp and even, then dusted with powdered sugar and flashed in a hot oven so the surface turns to a thin, shiny caramel that resists moisture.

The cream has to be firm enough to hold the stack without oozing, which is why it is cooked thick and chilled well. Assemble only a few hours before serving, since the pastry slowly softens on contact with the cream. Use a serrated knife and a gentle sawing motion; pressing down crushes the layers and squeezes out the filling.

Ingredients

• Pastry cream600 ml (2½ cups) whole milk
• 1 vanilla bean, split, or 1 tbsp vanilla bean paste
• 6 large egg yolks (about 110 g)
• 140 g (⅔ cup) granulated sugar
• 50 g (⅓ cup + 1 tbsp) cornstarch
• 40 g (3 tbsp) unsalted butter — cold, cubed
• Pastry500 g (1.1 lb) all-butter puff pastry — homemade or store-bought, chilled
• 30 g (¼ cup) powdered sugar — for caramelizing, plus more for serving

Method

1. Make the pastry cream. Heat the milk with the vanilla until steaming. Whisk the yolks, sugar and cornstarch until pale, then whisk in half the hot milk. Return everything to the pan.
2. Whisk constantly over medium heat until very thick, then let it bubble for 2 minutes while whisking. Off the heat, whisk in the butter. Spread in a shallow dish, press plastic wrap onto the surface and refrigerate for at least 2 hours.
3. Roll the puff pastry on a lightly floured surface into a 30 × 40 cm (12 × 16 in) rectangle about 2–3 mm thick. Move it to a parchment-lined baking sheet, prick it all over with a fork and refrigerate for 20 minutes. Heat the oven to 200°C (400°F).
4. Cover the pastry with a second sheet of parchment and set the other baking sheet on top to keep it flat. Bake for 20 to 25 minutes, until pale golden.
5. Remove the top sheet and parchment and bake 5 to 10 minutes more, until evenly deep golden. Increase the oven to 230°C (450°F). Sift the powdered sugar evenly over the pastry and return it to the oven for 2 to 4 minutes, watching closely, until the sugar melts into a glossy amber glaze. Cool completely.
6. With a serrated knife and ruler, trim the edges and cut the pastry into three equal strips, each about 10 × 28 cm (4 × 11 in). Save the neatest strip for the top.
7. Whisk the cold pastry cream until smooth and spoon it into the piping bag. Pipe neat rows of cream over one strip, about 1.5 cm high. Top with the second strip, pressing very gently, and pipe the second cream layer.
8. Set the best strip on top, glazed side up. Refrigerate for 1 hour to firm up. Dust the edges with powdered sugar, then cut into 8 slices with the serrated knife, sawing gently.

Tips for success

• Bake the pastry the day before if it suits you. Store it airtight at room temperature and assemble on the day.
• If the caramelized sugar burns in spots, scrape them lightly with the knife; a small amount of dark color tastes fine.
• Chill the assembled pastry before slicing. Cold cream cuts cleanly; soft cream squeezes out the sides.

Substitutions

Pastry cream

Fold 120 ml whipped heavy cream into the chilled pastry cream to make a lighter diplomat cream. It tastes airier but is softer and harder to slice cleanly.

Caramelized top

Spread the top strip with white fondant icing and feather it with lines of melted chocolate for the classic bakery look.

Store-bought puff pastry

An all-butter brand tastes far better than one made with vegetable fat. Homemade rough puff pastry rises a little less but works well here.

Variations

Raspberry mille-feuille

Alternate fresh raspberries with dots of pastry cream on each layer for a fruit version.

Individual napoleons

Cut each baked strip into 8 rectangles before assembling, then stack each portion separately.

Troubleshooting

Pastry rose unevenly and puffed in spots

It was not docked well or the weight was too light. Prick the entire surface and press with a heavy baking sheet.

Cream oozes out when sliced

It was too soft or not chilled. Boil the cream for the full 2 minutes and chill the assembled pastry before cutting.

Layers are soft

The pastry was underbaked or assembled too early. Bake until deep golden all through and assemble within 4 hours of serving.

Storage

Serve mille-feuille within 6 hours of assembly. Keep it refrigerated, covered loosely, and do not leave it out more than 2 hours. Baked, unfilled pastry keeps airtight at room temperature for 2 days. The pastry cream keeps for up to 3 days in the refrigerator.

Safety notes

The pastry cream is boiled, which cooks the yolks thoroughly. It is perishable, so refrigerate it and the finished dessert. Contains wheat, egg and milk.