1. Bake pastry shells according to package. directions.
2. Slice beef into very thin strips.
3. Heat half the oil in skillet. Add beef and cook until browned, stirring often. Remove beef.
4. Heat remaining oil. Add mushrooms, onion, garlic and thyme and cook until tender.
5. Add gravy and heat to a boil. Reduce heat to low. Stir in sour cream. Return beef to pan and heat through. Serve in pastry shells. Garnish with parsley.