Thaw the puff pastry. If frozen, thaw the puff pastry according to the package directions.
It should be pliable enough to unfold without cracking but still cool to the touch.
Mix the sugar and cinnamon in a bowl.
Sprinkle some of the mixture over a clean work surface, then lay the puff pastry on top.
Sprinkle more cinnamon sugar over the dough.
Use a rolling pin to gently roll the pastry and press the cinnamon sugar into the surface.
Turn the dough and repeat on the other side.
Press the cinnamon and sugar down on the dough.
Fold about 1 inch of one long side toward the center. Repeat with the opposite side.
Continue folding both sides inward until they meet, then fold one side over the other to form a long, layered strip.
Keep the folds as even as possible. Leave enough room to fold one side over the other at the end.
Using a sharp knife, cut the folded pastry into slices about 1 inch thick.
Dip the cut sides into the remaining cinnamon sugar.
Arrange the slices on a parchment-lined baking sheet, leaving space between them so they can expand.
Refrigerate for 15 minutes before baking.
Preheat the oven to 375°F. Bake the orejas for about 20 minutes, or until puffed and golden.
Carefully flip them and bake for another 5 minutes, until both sides are crisp and the sugar is caramelized.
Let them cool slightly on the baking sheet before transferring them to a rack. The melted sugar will be hot, and the cookies will become crisper as they cool.
Once cool, serve and enjoy!