1. Heat oven to 400 degrees . Coat four 11/2-cup ramekins with nonstick cooking spray (see Note).
2. Heat 1 tbsp of the oil in a large nonstick skillet over medium-high heat. Add chicken and cook 5 minutes, turning once. Remove and place on a plate.
3. Add remaining 1 tbsp oil, the onion, pepper, mushrooms, carrots and celery. Cook 5 minutes, stirring occasionally. Add flour, shawarma seasoning, salt and pepper. Cook 1 minute. Gradually stir in broth and milk; simmer until thickened, about 2 minutes. Return chicken to skillet and add peas. Stir to combine.
4. Spoon a generous 1 1/2 cups of the mixture into each prepared ramekin.
5. Unroll pastry sheets and cut two 5-inch circles from each (1/2 inch wider than ramekin). Place a piece of pastry over each ramekin, tuck under and flute. Brush each with egg. Make a vent in center of each with a small knife.
6. Place on a baking sheet and bake at 400 degrees for 25 minutes. Cool slightly.Notes
7. Note: Look for shawarma seasoning in your supermarket's international foods aisle or in a specialty store.
8. Note: For one large pie, spoon chicken mixture into an 11 x 8-inch baking dish. Fit pastry over top, vent in a few places and brush with egg. Bake at 400 degrees for 30 to 35 minutes, until browned and bubbly.