Line 2 sheet pans with parchment paper. Set aside.
Heat oven to 425°F.
Cut pastry into 9 equal squares.
On a lightly floured surface, roll each square to 1/16 inch thickness.
Top each square with 1 slice prosciutto.
Place 1 slice of brie and 4-6 asparagus spears at an angle on top of prosciutto.
Fold top right corner of pastry over asparagus.
Fold bottom left corner over bundle and tuck under.
Use a small pastry brush to brush egg wash over all exposed pastry.
Place in freezer for 10-15 minutes.
Bake for 20 minutes, or until puffed and golden brown.