Cut the peaches in half, take out the pit and then cut into 1/4 inch slices. Set aside.
Preheat your oven to 350 degrees.
Split the puff pastry in the box in half. Sprinkle a surface with a little flour and roll out the puff pastry into a rectangle approx 11 x 7 inches then take a sharp knife and cut the rectangle in half lengthwise. Pick up the pastry and place it on a parchment lined baking tray. Repeat with the second half of puff pastry. (trust me, you will want four of these). Using the knife, score the edges of the puff pastry about 1/2 an inch from the edge all the way around.
Cut the round of brie in half and then cut off all the wax around the edges (unless you like to eat that part). Cut the cheese into 1/4 inch thick slices. First lay the brie on the tart evenly spaced. Don't cover the whole pastry, leave some room in between slices.
Next lay the peach slices on the brie and follow with chunks of the prosciutto. Just tear the proscuitto slices up with you hands and place on the tart. Drizzle 1 tbsp the honey on top of each tart and throw it in the oven for 12 mins or until the edges are nice and puffed and browned.
Remove the tart from the oven, drizzle with 1 more tbsp of honey and 1 tbsp of the balsamic reduction on each tart. Cut into pieces and serve right away.
If you choose to make all 4 tarts, I would bake two at a time unless you are serving more than 8 people.