Sprinkle 2 tablespoons (25g) of sparkling sugar on your work surface. Place 1 puff pastry sheet on the sugared surface. Sprinkle evenly with 2 tablespoons (25g)of sparkling sugar. Roll gently with a rolling pin, pressing the sugar into the dough.
Roll the short ends of the puff pastry sheet in towards the center, jelly roll style, leaving a 1-inch gap in the center. Repeat the steps with the remaining puff pastry sheet. Transfer the puff pastry rolls to a tray. Cover with plastic wrap and chill in the refrigerator for 30 minutes.
Preheat the oven to 400°F (205ºC). Line 2 large baking sheets with parchment paper.
Slice each roll into 1/2-inch slices. Place the slices 2 inches apart onto the prepared baking sheets, cut side down, forming into heart shapes. Sprinkle any remaining sparkling sugar over the hearts.
Bake until 15-17 minutes, until golden brown. Transfer to a cooling rack to cool before serving.
Notes
Palmiers are best served the day they are made. Store in an airtight container for up to a few days.