Defrost puff pastry to room temperature, cut into ten 2,5 -3 inches squares
Place the chopped walnuts into the frying pan and toast walnuts for about 3-5 minutes on medium heat, tossing often
In a saucepan combine raspberries and sugar, cook for about 3-5 minutes (you want some of the raspberries to become saucy and some to still remain their shape)
Preheat the oven to 400 F
If using big brie, remove from package and cut it in 10 pieces; if using small brie, remove the packaging
On each pastry square, place 1 teaspoon walnuts in the center, add brie, and top it with 1 teaspoon of raspberry sauce
Seal all the pastry edges and brush it with a beaten egg
Place brie packages on the baking sheet at least 1 inch apart and bake for 12-14 minutes until golden brown.
Serve with the remaining walnuts and raspberry sauce.