In small bowl, combine sugar, pumpkin pie spice, and salt.

On a large flat piece of plastic wrap, pour about a third of the sugar mixture and create an even layer that's about 10x10 inches in size.

Lay your first puff pastry sheet on top of the sugar. Sprinkle with two tablespoons of the sugar mixture and then top with the second puff pastry sheet. Top that with the remaining sugar mixture.

Roll that stack in one direction only to press the sugar into the dough and to lengthen the 10x10 square into a 10x12 rectangle.

With the long edge facing you, tightly roll up the left and right sides until they meet in the middle, leaving you with a 10 inch long roll. Wrap tightly with plastic wrap and store in the freezer for 45 minutes.

Preheat the oven to 375 degrees F and line two baking sheets with a silpat or parchment paper.

Take the wrapped dough out of the freezer. Using a very sharp knife, divide the dough into half and store half of it in the freezer until you're ready to bake the second batch. If you don't want big expanded cookies and like to keep them petite and uniform, its crucial you bake chilled dough.

Slice first half into 3/8 inch thick slices. You should get about 12 slices. Don't worry about the end piece being ugly - you'll get to eat it as soon as it comes out of the oven. Bake in preheated oven just until the cookies start to get golden, about 14-16 minutes. Flip them and bake for another 4-6 minutes. Immediately transfer to a cooling rack. These are not the kind of cookies you want to leave on a warm baking sheet. Follow the same steps with the second half of the dough.

Store in an airtight container.