Heat the oven to 375 F and lay out one of your puff pastry sheets on a the counter or a cutting board
Sprinkle half your Gruyère cheese and parmesan cheese onto the puff pastry sheet
Fold the puff pastry sheet in half and roll out with a rolling pin (or press down using your hands) to press everything down ensuring the cheese does not fall out of the puff pastry sheet
Then add on your egg wash on top of your puff pastry sheet and sprinkle on the remainder of your Gruyère cheese and Parmesan cheese
Cut into strips (you can use a knife but I found it easiest to use a pizza cutter)
Then twist each strip and put on a sheet pan lined with parchment paper
Bake for 15-20 minutes until golden brown and serve right away!
