- Preheat oven to 400°F. Heat olive oil in large saucepan over medium-high heat. Add onion and cook until tender, about 5 minutes. Add chicken, peas and carrots, and cook until heated through, about 3 minutes. Stir in gravy, and remove from heat.
- Unfold puff pastry and cut each sheet into 12 even squares. Portion filling evenly into the center of 6 pastry squares. Top with remaining pastry squares. Pinch the edges to seal using fingers or a fork.
- Using a sharp knife cut 2 small slits into the top of each pocket. Transfer pockets to prepared baking sheet and brush with egg. Bake until golden-brown, about 10 to 15 minutes.
Tip: Substitute pie dough for puff pastry!