preheat oven to 450°. Prepare pastry for single crust pie. On a lightly floured surface roll pastry from the center to edges into a circle about 12 inches in diameter. Wrap pastry circle around the rolling pin. Add rolled into a 9 inch pie plate. Ease pastry into pie plate without stretching it. Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry even with the plates edge. Crimp edge as desired. Do not prick pastry.
Line pastry shell with a double thickness of heavy foil. Bake for eight minutes; remove foil. Bake for 6 to 8 minutes more or until pastry is golden. Remove from oven. Reduce oven temperature to 350°.
Meanwhile in a large skillet cook bacon over medium heat until crisp. Using a slotted spoon, transfer bacon to a paper towel. Wipe out skillet.
In the same skillet melt butter over medium heat. Whisk in flour, mustard, and pepper. Cook and stir for two minutes. Whisk in milk, green onions, and Worcestershire sauce. Cook and stir until thickened and bubbly. Reduce heat to low. Add cheddar cheese; stir until cheese melts. Remove from heat.
Stir macaroni, bacon, and corn into cheese mixture. Spoon macaroni mixture into baked pastry shell, mounding mixture in the center.
Bake, uncovered, for 25 to 30 minutes or until heated through. If needed, cover edge of crust with foil to prevent over Browning. If desired, sprinkle with sliced green onions before serving. Makes 10 servings.
Note: pastry for single crust pie: medium bowl stir together 1 1/2 cups flour and 1/2 teaspoons salt. Using a pastry blender, cut in 1/4 cup shortening and 1/4 cup cut up butter until pieces are pea size. Sprinkle 1 tablespoon ice water over part of the flour mixture; toss gently with a fork. Push moistened dough to the side of the bowl. Repeat with additional ice water, 1 tablespoon at a time, for a total of 1/4 to 1/3 cup total, until all of the flour mixture is moistened. Gather flour into a ball and gently knead until holds together.