Preheat the oven to 400 degrees and prepare a baking sheet by lining with parchment paper. Set aside.
In a medium bowl, beat together cream cheese, sugar, egg yolk and vanilla extract until smooth. Set aside.
Unroll the puff pastry while it's still slightly chilled. Cut into 6 equal rectangular pieces. Place each piece on the prepared baking sheet with the short sides facing you.
Using a sharp knife or a pizza cutter, make small slits up the long sides of each rectangle, as you would if you were making a large pastry braid.
Spread about a tablespoon or so of the cream cheese filling down the center strip. Place berries in a line down the center of each rectangle.
Starting at the top, pull the strips of puff pastry dough across the center of each rectangle, alternating sides to create the "mummy wrap". Continue to "braid" all the way down to the end of each rectangle until all mummies are complete.
Bake for 18-20 minutes or until puffed and golden.
Remove from oven and allow to cool completely.