This traditional French dessert, called a napoleon in America, is quite simple once you’ve made the dough: it’s essentially puff pastry and a mousseline cream. Sebastien never liked how difficult it was to cut the mille-feuille into slices: you inevitably press out some of the cream as you cut down through the layers of pastry. So, he thought, why not serve it on its side, as it were, so that you cut through the layers of pastry at the same time without compressing the cream filling? It’s an ingenious solution. Served this way, it slices beautifully. We decorate it with whipped cream piped through a St.-Honore tip, a flat fluted tip, to make teardrop shapes. Garnish it with a whole vanilla bean, if you like.
Ingredients
Mousseline
- 1½ cups + 2½ tablespoons (375 grams) Pastry Cream
- 2½ cups (375 grams) Basic Buttercream
- 21 ounces (600 grams) Puff Pastry
- 3 cups (300 grams) Sweetened Whipped Cream
- 1 vanilla bean, split lengthwise
How to Make It
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For the Mousseline
- Place the pastry cream in the bowl of a stand mixer fitted with the whisk attachment and whip on medium speed until smooth. Add the buttercream and whip until well combined.
- Line the baking pan with plastic wrap so that it extends slightly over all four sides (use two sheets if necessary, overlapping them slightly). Pour the mousseline into the pan and smooth the top with an offset spatula. Freeze overnight. To Roll Out the Pastry
- Lightly flour the work surface and a rolling pin. Lightly dust the top of the puff pastiy and roll it outward from the center, flipping, fluffing, and rotating it and turning it over, adding only enough flour to the work surface, dough, and/or pin as necessary to prevent sticking. Roll the dough to a 12½-by-16-inch rectangle. If the dough becomes too difficult to roll, place it on a sheet pan and refrigerate until cold, then return it to the work surface and continue to roll it.
- Set the dough on a sheet pan and refrigerate it for at least 1 hour, or freeze for 30 minutes, to chill and relax. To Bake the Dough
- Preheat the oven to 350°F (standard).
- Cut a piece of parchment paper the size of the sheet pan. Lay the parchment paper on top of the dough and, using a pizza wheel or a large chef’s knife, trim the dough to the size of the sheet.
- Spray the sheet pan lightly with nonstick spray and line it with parchment paper. Roll the puff pastry up on the rolling pin and unroll it on the lined sheet pan. Place the sheet pan in the freezer for 5 to 10 minutes, or refrigerate it for about 20 minutes, until the puff pastiy is cold.
- Top the puff pastiy with a piece of parchment paper and another sheet pan. If you have them, add up to three more sheet pans to weight the dough and keep it veiy flat. If you don’t, set other weights, such as baking pans, on top; be sure that the weight is evenly distributed. Bake for 1 hour and 10 minutes, or until the bottom of the pastiy is a rich golden brown.
- Remove the sheet and/or baking pans from the top of the pastiy, but leave the parchment paper in place. Invert the pastiy onto the back of a sheet pan. Cover the pastry with a piece of parchment and another sheet pan. Bake for another 15 minutes, or until the bottom is light golden brown.
- Remove the top sheet pan and parchment paper and bake for 8 to 10 minutes more, until the pastry is cooked through and a very rich golden brown. Remove from the oven and let the pastiy cool on the pan on a cooling rack. To Assemble the Mille-Feuille
- Carefully transfer the pastry to a cutting board. Using a serrated knife, trim the edges to make a 10-by-12-inch rectangle. To cut 4 lengthwise strips of pastiy, first cut marks eveiy 2½ inches on both ends of the pastry. Carefully use a sawing motion to cut the pastry in a straight line from one end to the other. (If you aren’t assembling the mille-feuille immediately, place the pieces on a parchment-lined sheet pan, wrap completely in plastic wrap, and set aside for up to 1 day.)
- Turn the frozen mousseline out onto a cutting board. Trim the edges to even them. Measure the finished puff pastiy strips and cut the mousseline into 3 matching strips; you may have extra mousseline.
- Place one strip of puff pastiy on a serving platter or board. Top with a strip of mousseline, and repeat the layering with the remaining puff pastiy and mousseline. Turn the mille-feuille on its side. (It is much easier to slice the mille-feuille with this presentation.)
- Place the whipped cream in the pastiy bag and, starting in one corner, holding the tip with the opening facing up, pipe a line of teardrops (moving the bag slightly forward, then raising it slightly and pulling back to form the bottom of each teardrop) onto the mille- feuille. Work vertically in one line, piping one from the right, then one from the left to form a V. Repeat to cover the entire surface. If you will be garnishing the top with the vanilla bean, pipe a few more teardrops to anchor the bean. Arrange the vanilla bean atop them on an angle. Refrigerate until ready to serve.
- The mille-feuille should be served the day it is assembled, and it is at its best if refrigerated for no more than 2 hours. Use a serrated knife to cut it into 2-inch slices.
