Step 1

To make the dough: In the bowl of a stand mixer fitted with the dough hook, combine the water, salt, flour, and butter. Mix on speed 2 until the dough just comes together, about 5 minutes. It’ll be fairly rough and chunky; don’t worry.

Step 2

, Transfer the dough to a parchment-lined baking sheet and shape it into a rough 8” x 6” rectangle. Cover securely with plastic wrap or a reusable cover and refrigerate for at least 1 hour.

Step 3

, To make the butter block: In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and cake flour, mixing until smooth and paste-like.

Step 4

, Transfer the butter mixture to a piece of parchment and place a second piece of parchment on top. Using a rolling pin, shape it into an 8 1/2” x 12 1/2” rectangle; this is your butter block. Chill for 10 minutes to firm up, then use a bench knife or chef’s knife to trim just enough from the edges to make a perfectly rectangular block.

Step 5

, Refrigerate the butter block before using to firm the butter up, about 30 minutes. It’s important to get the temperature just right here: too cold and the block will break into pieces; too warm, it’ll melt. When ready, the butter block will be cold, but will still bend without breaking.

Step 6

, To prepare and roll the dough : Place the chilled butter block on a lightly floured work surface. Place the dough block on the lower half of the butter block. Fold the top half of the butter block over the dough, like a turnover, and press on the three open edges to “lock in” the dough.

Step 7

, Turn the dough 90º and roll it into a 10” x 16” rectangle. Fold the dough in thirds like a letter; this is called a letter fold. Turn it 90º, re-roll into a 10” x 16” rectangle, and perform another letter fold.

Step 8

, Wrap the dough securely in plastic wrap or a reusable wrap, and refrigerate for 1 hour. Repeat step #7, rolling and folding twice.

Step 9

, Cover the dough and refrigerate it for at least 2 hours (overnight is fine) before using.

Step 10

, Use the dough to make your favorite flaky pastries. Or freeze it, well wrapped, for up to 1 month before using.

Step 11

, To make the maple cream filling: In a medium-sized saucepan, stir together 2 1/2 cups (568g) of the milk, the maple sugar, and the salt. Bring to a simmer over medium heat, stirring to dissolve the sugar. Meanwhile, whisk the cornstarch, flour, and egg yolks with the remaining 1/2 cup (113g) milk.

Step 12

, Whisk some of the hot milk mixture with the egg yolk mixture to temper the yolks, then pour it back into the remaining simmering milk. Doing this through a strainer will help prevent lumps later. Bring to a boil, stirring constantly with a whisk, until the mixture thickens and the boiling bubbles reach the center of the saucepan.

Step 13

, Remove the mixture from the heat and strain it through a fine strainer into a bowl set in a larger bowl of ice water. Stir in the butter and vanilla extract.

Step 14

, Rub a piece of butter over the surface of the pastry cream, top with a piece of plastic wrap (make sure it touches the top of the cream so it doesn't develop a skin), then refrigerate until cool.

Step 15

, To make the napoleons: Preheat your oven to 375°F with a rack in the middle.

Step 16

, Portion off a generous one-third of the pastry dough; use the remainder for something else, or wrap and freeze for later.

Step 17

, Roll the pastry into a 1/8”-thick rectangle, about 11” x 16”. Place it into a parchment-lined half-sheet pan (12” x 18” baking sheet).

Step 18

, Place a piece of parchment on top of the pastry, then put a second half-sheet pan on top; weigh it down with a cast iron pan, bricks, or something else heavy and oven-proof. Counterintuitively, you don’t want the puff pastry to puff too much; it should remain fairly flat as it bakes, thus the weights.

Step 19

, Bake the pastry for 20 minutes, then remove the weights, top pan, and top piece of parchment. Continue baking until the pastry is a deep golden brown, 10 to 20 minutes more. Remove the pastry and cool it right on the pan. Trim the ragged edges before using.

Step 20

, To assemble the napoleons: Cut the pastry in half crosswise, so you have two pieces about 10” x 7 1/2”. Cut each half into five strips lengthwise, to make 2” (approximately) x 7 1/2” strips.

Step 21

, Place five pastry strips on a clean work surface. Pipe the chilled pastry cream onto the strips. Top with the remaining five pastry strips, and pipe the remaining pastry cream on top.

Step 22

, Garnish, if desired, with caramelized sugar drops: Melt the granulated sugar in a heavy saucepan until it’s starting to color. Carefully drop half-teaspoonfuls onto a piece of parchment; the sugar will continue to brown and at the end you’ll have a mixture of lighter and darker drops.

Step 23

, Serve the napoleons immediately, or chill briefly, lightly covered, before serving.

Step 24

, Storage information: Store any leftover napoleons, well wrapped, in the refrigerator for up to a day or so; the pastries are best enjoyed within 24 hours of their assembly. That said, it's possible to make and store both the pastry and pastry cream several days ahead, then assemble the napoleons shortly before serving.