Thaw the puff pastry sheet according to package directions. It usually needs to sit out for 35-40 minutes to unfold without breaking.
Preheat the oven to 400ºF. Line a baking sheet with parchment paper.
In a small bowl, whisk together the egg and water.
Lay the puff pastry sheet out flat. (You can roll it out slightly on a floured surface if you'd like, but I don't find this is necessary.)
Place the brie in the center of the puff pastry. Spread the blackberry jam on top of the brie (use anywhere from 1/3 cup to 1/2 cup jam).
Take one edge of the puff pastry and place it up over the brie. Brush the top of the dough lightly with the egg wash. Bring another piece of the pastry up over the brie, brush with egg wash. Continue to do this until the brie is completely wrapped tightly with no air inside.
Brush the top of the wrapped brie with any remaining egg wash. Cut 2-3 1/2" slits into the top of the pastry to that it can vent.
Place the wrapped brie on the prepared baking sheet.
Bake for 25-28 minutes or until the brie is golden brown.
Sprinkle fresh thyme leaves on the top and serve with crackers, fruit, and bread.
Refer to the article above for more tips and tricks.The calories shown are based on the recipe serving 8 people, with 1 serving being 1/8 of the cheese. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**