On a work surface, place the chicken breasts between sheets of plastic wrap and pound to 1/4-inch thickness. Split each breast width-wise and trim a little off of each end, creating a square.
Season each breast with garlic powder and lay a piece of prosciutto on top of one side of each breast. Top with a slice of provolone. Sprinkle with the goat cheese and Gruyer, dividing them equally.
Fold the empty side of the breast over to create a square pouch. Refrigerate for 1 hour.
Preheat oven to 350 degrees. Line a rimmed baking sheet with parchment paper.
Arrange the puff pastry sheets on a lightly floured work surface. Brush the edges with melted butter.
Place a chicken and cheese parcel in the center of each square. Fold the sides of sheet over to cover filling. Brush again with butter, then fold both ends over. Brush the tops of each package with melted butter.
Set the pastries on the prepared baking sheet and bake for 10 to 15 minutes, until the internal temperature of the chicken reaches 165 degrees.
Remove from the oven and cool for 10 minutes.
Stir together all the ingredients for the dip in a small bowl and refrigerate until ready to use.
This tutorial is printed with permission from <a href="http://amzn.to/1pL5sol">"The Big Dish: Recipes to Dazzle and Amaze from America's Most Spectacular Restaurant"</a> by Barton G. Weiss and published by Rizzoli.