Preheat oven to 400° and line 2 large baking sheets with parchment. In a small bowl, combine butter, honey, and salt. In a medium bowl, toss asparagus in oil.
On a lightly floured surface, working one at a time, roll out puff pastry to a 15" x 10" rectangle. Cut each into 6 squares for a total of 12.
Rotate square to a diamond shape and brush with butter mixture. Top with a slice of prosciutto, folding as needed to fit inside square. Top with a few pieces of asparagus and a slice of brie.
In a small bowl, mix egg and a splash of water until blended. Fold left side of pastry over filling and brush with egg wash. Fold right side of pastry over and brush top and sides with more egg wash; season with pepper. Arrange on prepared sheet. Repeat with remaining puff pastry; reserve any remaining butter mixture.
Bake bundles until golden and brie is melted, about 15 minutes.
Brush with more reserved butter mixture before serving.
