Step 1: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Step 2: Gently unfold the thawed puff pastry sheet on a lightly floured surface. Using a 3-inch star-shaped cookie cutter, cut out 12 stars. Gather any scraps, re-roll once if needed, and cut additional stars. Place the stars on the prepared baking sheet.
Step 3: Using a smaller star-shaped cookie cutter (about 1.5-2 inches) or a knife, lightly score a smaller star shape inside each large puff pastry star, leaving a 1/4-inch border. Be careful not to cut all the way through the pastry.
Step 4: Prick the center of each scored star several times with a fork. Brush the entire surface of each puff pastry star lightly with the beaten egg wash.
Step 5: Bake for 12-15 minutes, or until the puff pastry is golden brown and puffed. The inner scored section should rise, creating a small well. Remove from the oven and let cool slightly on a wire rack.
Step 6: While the pastry bakes, prepare the chicken salad. In a medium bowl, combine the shredded chicken, mayonnaise, dried cranberries, toasted pecans, diced celery, minced chives, and Dijon mustard. Mix well until everything is evenly coated.
Step 7: Season the chicken salad with salt and pepper to taste. Adjust seasonings as desired.
Step 8: Once the puff pastry stars have cooled enough to handle, use a small spoon or your fingers to gently press down the puffed inner section of each star, creating a deeper well for the filling.
Step 9: Spoon approximately 1-2 tablespoons of the cranberry pecan chicken salad into the center of each puff pastry star. Garnish with fresh parsley or additional chives, if desired.
Step 10: Serve immediately or chill for later. These are best enjoyed within a few hours of assembly for optimal pastry flakiness, but can be made ahead.