Prepare pastry. Roll pastry into a 12" circle. Cover and set aside. In a medium saucepan cook potato and onion in butter over medium heat, stirring constantly, for 5-6 minutes or till onion is tender but not brown. Stir in flour, herb and 1/8 teaspoon pepper. Add broth all at once. Stir in peas and carrots. Cook and stir till bubbly.
Stir in meat. Transfer mixture to a 1 1/2 quart casserole. Top with pastry; trim pastry to 1/2" beyond rim. Turn under and flute edges of pastry. Cut slits for steam. Place on a baking sheet. Bake in a 425F degree oven for 25-30 minutes or till golden. Let stand 10 minutes.