Preheat oven to 425°F.
Line cookie sheets with parchment paper.
Dust your work surface (cutting board, butchers block or counter) liberally with sugar.
Place thawed puff pastry sheet on top of sugar.
Sprinkle top of puff pastry with a bit of sugar, gently spread and even out with your hand.
Roll out pastry to a rectangle, about 1/8" thickness.
Find the center of your pastry. Tightly, but gently, roll each long side to the center of the pastry. The two sides will meet in the center.
Dust a plate or cutting board with sugar, carefully transfer rolled puff pastry onto it, and chill in fridge for about 15 minutes.
While waiting, fill a small bowl with remaining sugar and a sprinkle of cocoa powder & cinnamon (if desired).
Return pastry back to work surface. Cut pastry roll into 12 slices.
Gently dip both sides of the slices in sugar and transfer to cookie sheet.
Bake for 6 - 8 minutes, flip and bake another 5 - 8 minutes until golden brown.
Let palmiers rest for a minute on cookie sheet then transfer to wire rack and cool.