1. Preheat the oven to 350 degrees Fahrenheit. Grease a baking sheet or dish.
2. Place chicken breasts on baking sheet or dish, and season with salt, pepper, and garlic powder. Bake for 20 minutes or until juices run clear. Set aside to cool. Dice chicken when cooled.
3. In a small bowl, combine diced chicken, parve cream cheese, margarine, and scallions.
4. Lay out the squares of puff pastry and spoon one tablespoon of the chicken mixture into the center of each square. Pull the opposite corners to meet in the middle and pinch closed into an envelope.
5. Brush egg over pastry. Bake until golden, about 25 minutes.