1. Preheat oven to 425°.
2. To prepare filling, heat oil in a large saucepan over medium-high heat. Add onion, carrot, and celery; sauté 4 minutes. Add garlic; sauté 30 seconds. Weigh or lightly spoon 1.1 ounces (1/4 cup) flour into a dry measuring cup; level with a knife. Stir flour, salt, and pepper into vegetables; cook 1 minute, stirring constantly. Stir in stock; bring to a boil. Reduce heat to medium; simmer 8 minutes, stirring occasionally. Stir in chicken and peas; simmer 5 minutes. Remove from heat. Remove rosemary from herb package; reserve for another use. Strip leaves from stems of remaining herbs; chop leaves to measure 2 tablespoons. Stir herbs into filling. Pour filling in a 2-quart baking dish or cast-iron skillet coated with cooking spray.
3. Cut a 9-inch circle of refrigerated pie dough into 3/4-inch-wide strips. Weave strips over filling; coat with cooking spray. Bake at 425° for 30 minutes. May be prepared in 6 (10-ounce) ramekins.