For the cronut, place both puff pastries on the floured work surface and cut in half to make 4 pastry sheets. (If you prefer, you can of course prepare the puff pastry yourself using this basic recipe). Place these four pastry sheets on top of each other and roll over them with a rolling pin so that the dough becomes a homogeneous whole.
Now cut out four circles with a diameter of about 10 cm from the puff pastry with a very sharp knife. Cut a small hole in the center or cut out with a round cookie cutter so that the cronut gets the typical donut shape.
Heat the oil in a pan and fry the cronut in it until it has a crispy brown color on both sides.
If desired, mix the cinnamon and sugar together and roll the top of the cronut in it, serving it lukewarm.