Preheat the oven to 400℉. Line 2 large baking sheets with parchment paper.

Mix the sugar and cinnamon in a small bowl. Reserve 3 tablespoons of the mixture and set it aside to use for topping at the end.

On a well-floured surface, roll each sheet of puff pastry to a 13x17-inch rectangle.

Sprinkle half of the cinnamon sugar onto the work surface and stack the 4 sheets of rolled-out dough on top of each other to create one large sheet.

Sprinkle the remaining half of the cinnamon sugar on top and roll it out into a large rectangle, approximately 17x22 inches.

Make an indentation in the dough with the rolling pin all the way down the middle the long way to mark the center of the puff pastry.

Starting at one of the long ends, fold the dough halfway to the center, then fold once more. Repeat on the other side.

Fold both sides together like a book, then slice off any scraggly ends and discard.

Cut into ½-inch slices and arrange them open-faced in an even layer on the baking sheet. Sprinkle the remaining cinnamon sugar on top.

Bake for 10-12 minutes, until the bottom side is golden brown and caramelized. Then, flip and bake for an additional 10 minutes, until golden brown and crispy.

Allow to cool slightly and serve.