Divide pastry into fourths. On a lightly floured surface, roll out one portion to fit a 9-in. pie plate. In a large bowl, combine the next seven ingredients; crumble beef over mixture and mix well. Spoon half into crust.
Roll out another portion of pastry to fit top of pie; place over filling and seal edges. Cut vents in top pastry. Repeat with remaining pastry and filling. Cover and freeze one pie for up to 3 months.
Bake second pie at 375° for 15 minutes. Reduce heat; bake at 350° for 1 hour. Meanwhile, drain mushrooms, reserving liquid. Add water to liquid to measure 1 cup; set aside.
In a small saucepan, cook mushrooms and flour in oil until bubbly. Remove from the heat; stir in bouillon and reserved mushroom liquid. Bring to a boil; cook and stir for 1 minute or until thickened. Stir in browning sauce if desired. Serve with pie.
To use frozen pie: Bake at 375° for 70 minutes. Prepare gravy as directed. Serve with pie. Yield: 2 pies (6-8 servings each).
