Flour a clean surface. Remove the frozen puff pastry from the cardboard box and paper container. Let it thaw for 25-30 minutes or until it can be opened up without the folds breaking.
Once thawed, unfold the puff pastry sheets. Remove the small pieces of parchment paper inside the puff pastry. Sprinkle some flour on the top of the puff pastry sheets.
Roll the sheets a little just to flatten them. Using a ruler and knife, measure and cut 6 squares from the puff pastry to a 3 inch by 4 ½ inch each. There will be little extra, but some. Discard.
Repeat measuring and cutting with the other sheet. You'll have 12 squares all together. Set aside.
In a small dish, add in the brown sugar and cinnamon. Stir until combined.
Measure out and rinse your raspberries. Dry thoroughly.
Using a pastry brush, brush the beaten egg on one side of the puff pastry. Add 2 - 3 teaspoons of the brown sugar, 2 slices of brie, and 3 raspberries. Add a clean puff pastry square to the top. Give a gentle press and do any stretching to have the sides meet each other. Press all sides firmly down with a fork to seal them.
Repeat with 5 other puff pockets.
Preheat oven to 375 degrees.
Place the puff pockets onto the parchment lined baking pan. Place into the freezer until firm, about 15 minutes.
Remove from the freezer and brush the egg wash over all of the pockets.
Place into the oven to bake for 23 minutes or until golden brown.