These are literally the easiest cookies I have ever made, and they are elegant enough to work for any occasion. I don't remember where we originally found the recipe, but my mom and I made them for one of last year's holiday dinners and I couldn't stop eating them. I made them again for a friend's housewarming party this past weekend and had about a dozen of them (just the burnt and broken ones, you know) before I left for her place. The recipe makes about four dozen cookies total and could be modified in a million ways.
2 sheets puff pastry
2/3 cup white sugar
2 tsp cinnamon
Thaw the puff pastry for about half an hour or until you can unfold the sheets without breaking them. Mix the cinnamon and sugar together in a small dish. Preheat the oven to 400ºF. Roll out one sheet a little (it should only get about 1" bigger all around) on a surface sprinkled with cinnamon sugar.
Sprinkle more cinnamon sugar onto the sheet, and start folding each side of the dough inwards until the two rolls meet in the middle. Repeat the process with the other sheet. The tighter the roll, the smaller the cookies will be, but the easier it will be to cut them.
If the dough is getting too soft to hold its shape, stick the rolls back in the freezer for a few minutes. Place on a cutting board with the smooth side up (the place the two rolls meet should be facing down), and use a sharp knife to cut 1/4" slices. Place on a baking sheet lined with parchment paper and sprinkle with more cinnamon sugar.
Bake for 10-15 minutes, adding more cinnamon sugar halfway through and rotating the baking sheet if one edge starts to burn. Cool on the baking sheets. If you make them the night before you can re-toast them for a few minutes before serving.