preheat oven to 400 degrees

pan spray one baking sheet

Flour your work surface and roll puff pastry to a 10x16 inch square, and until the seams are smooth. Place in the refridgerator and make the sauce. The puff pastry will be easier to roll when its cooled down a few degrees.

In a small pan combine the blueberries and sugar and tablespoon of water. Turn on low heat and let reduce until syrupy at least 10 minutes stirring occasionally. Use either a potato masher or a fork and crush most of the blueberries.

Add the fresh mint and fold into the blueberry sauce. Cool completely.

Whisk the egg with a fork in a small bowl and set aside. Take the puff pastry and blueberry sauce and place about 3 tablespoons in the middle of the puff pastry. Spread the sauce all over the puff pastry but leave the edges clean.

Fold in the left and right sides of the puff pastry about one inch. Fold the puff pastry equally on both sides until it meets in the middle.

Use a pastry brush to brush egg wash on the all exposed parts of puff pastry. Use a sharp knife and cut 12 slices in the puff pastry. Quickly place on a prepared baking sheet. Bake for 15 minutes or until edges are golden brown.

Let cool at least 5 minutes.