Set the puff pastry dough out to defrost for 40 minutes.

Meanwhile, set the blueberries in a small bowl and combine with approximately 1 tablespoon of the sugar. Place the chopped strawberries in another bowl and combine with remaining sugar. Set aside.

Place one sheet of dough on a lightly floured board and roll it out into a large rectangle, approximately 18 inches by 9 inches. Using a pizza dough cutter, cut the dough into six equal rectangles, approximately 9 inches long by 3 inches high.

Place a rounded tablespoonful of strawberries on the left-hand side of each rectangle. Leave a small space in the upper left hand corner and place six to eigh blueberries there. Then, using a pizza cutter, cut the right-hand side of the rectangle into "stripes" of dough, chopping off about an inch from the top three "stripes." Then carefully fold over the stripes from right to left, leaving the blueberry corner exposed.

Repeat with the second sheet of dough (so you have 12 flags total).

Mix together the egg and water, and brush the mixture over each flag. Bake at 400 degrees for 15 minutes or until golden brown and puffy.