Preheat oven to 425°F. Line baking sheet with parchment paper or a silicone baking mat. Combine the brown sugar, cinnamon, and salt in a bowl.
On a clean surface, evenly sprinkle ½ cup of the turbinado sugar. Lay first sheet of puff pastry on the sugar, and roll with a rolling pin to press into the sugar below it.
Top pastry evenly with brown sugar-cinnamon mixture.
Fold the sides of the puff pastry towards the center so they are halfway to the middle, and then fold both sides again so that they meet at the middle of the dough. Then fold one half over the other like a book.
Repeat steps 2-4 with the second puff pastry sheet.
Using a sharp knife, slice pastry rolls across into ¼ inch pieces and carefully lay on baking sheet 2 inches apart.
Bake for 6 minutes or until slightly browned on top. Remove from oven and, using a thin spatula, carefully flip pastry over. Bake for another 4-5 minutes until golden brown and caramelized. Cool completely before serving.
Storage: These cinnamon palmiers can be refrigerated or frozen, once cooled, in an airtight container. You may have to crisp them in the oven at 325 degrees for about 5-10 minutes after thawing.