Preheat oven to 350F
Take puff pastry out of the freezer and let sit on the counter for around 10 minutes.
In the meantime, cut the brie into squares
Unravel the puff pastry, and roll it out slightly with a rolling pin. Cut into 3 even rectangles lengthwise and then cut each rectangle to make 4 squares.
Place a square of brie onto each square, slightly off center. Add 1 tsp cranberry and a sprinkle of walnuts on top of the brie.
Close the square using one corner and bring it across to the opposite corner, forming a triangle. Press all of the edges together. *If you’re having trouble with the pastry sticking to itself, add a bit of egg wash. Add to a baking sheet.
Make an egg wash using 1 beaten egg and a splash of water. Brush each pastry and bake for 25 Minutes or until golden brown.