The first step is to place a piece of parchment paper over the counter and add half of the sugar and cinnamon to coat the surface evenly.
Then, place the pastry sheet on top and gently press over the sheet to ensure the sugar and cinnamon stick to the dough evenly.
Next, carefully flip the dough over and repeat the process on the other side, adding the rest of the sugar and cinnamon. The fine sugar granules will melt into the puff pastry as it bakes, creating a crisp finish with a hint of warmth from the cinnamon.
Preheat the oven to 400°F/204°C.
Use a sharp paring knife to cut the pastry into ½-inch-wide slices and place them on the lined baking sheet. Separate the tops of the cookies to make “bunny ears” to create a more defined heart shape (optional).
Bake the palmiers for 10–15 minutes until golden brown. Then, use a metal spatula to flip the cookies carefully and bake for another 2 minutes.
Transfer to a cooling rack and allow to cool completely.