Palmier Cookies

§ PROCEDURE

1. Make the puff pastry: combine 312 g flour, 200 g water, 25 g room-temperature butter, and a pinch of salt. Mix until a smooth dough forms — about 20 minutes by hand or 10 minutes in a stand mixer. Rest for 10 minutes. On a lightly floured surface, roll the dough into a square and encase 250 g of room-temperature butter in the center by folding the dough corners over it and pinching the seams shut. See the Cream Horns recipe for detailed puff pastry instructions.
2. Roll the butter-filled dough into a rectangle and perform at least 3 book folds: fold both short ends to the center, then fold the whole piece in half. Rotate 90 degrees between folds. Refrigerate between folds if the kitchen is warm. After the final fold, the puff pastry is ready.
3. Roll the puff pastry into a large rectangle, approximately 12 × 18 inches. Sprinkle half the sugar (about 75 g) generously and evenly over the entire surface. Press the sugar firmly into the dough with the rolling pin so it embeds into the surface.
4. Perform one more book fold: fold both short ends to the center, then fold in half. Roll the dough out again into a similar large rectangle. Sprinkle the remaining sugar over the surface and press in again with the rolling pin. The dough should have a visible, thick sugar coating.
5. Mark the center line of the rectangle lengthwise with a light indentation. Starting from one long edge, tightly roll the dough inward toward the center line in a compact scroll. Do the same from the opposite long edge. When both scrolls meet at the center, press them together gently so they adhere. You now have a double-scroll log.
6. Wrap the log tightly in plastic wrap and refrigerate for at least 30 minutes. This makes slicing much cleaner and helps the palmiers hold their shape in the oven.
7. Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper. Pour a thin layer of granulated sugar onto a flat plate. Slice the chilled log into rounds about ½ inch thick. Dip both cut faces of each round into the sugar, pressing lightly so it adheres, then place on the baking sheet, leaving at least 2 inches between them — they spread significantly as the sugar caramelizes.
8. Bake for about 10 minutes until the bottoms turn golden amber. Flip each palmier with a spatula and bake for another 8–10 minutes until both sides are deep golden and caramelized. Watch them closely near the end — the sugar darkens fast.
9. Transfer immediately to a cooling rack. Do not leave them sitting in the pooled sugar on the baking sheet or they will stick. The palmiers finish crisping as they cool.

§ OBSERVED RESULT

The cookies emerge with a lacquered amber underside where the sugar made direct contact with the baking sheet. Once flipped, both sides reach the same caramelized finish. Warm from the oven they are slightly yielding; within minutes of cooling they harden into crisp, flaky layers that shatter on first bite. Earth specimens describe the sound as satisfying. I have replicated this observation many times in the name of science.