Heat oven to 425°F. Place pie crust in 9-inch quiche or glass pie pan as directed on box for One-Crust Filled Pie. Bake 5 minutes. Remove from oven; reduce oven temperature to 350°F.
Meanwhile, in 8-inch skillet, cook ground beef over medium-high heat, stirring frequently, until thoroughly cooked; drain. Stir in mushrooms, Italian seasoning and garlic. Cook 2 to 3 minutes, stirring occasionally, until mixture is thoroughly heated.
Spoon mixture into partially baked crust. Top evenly with pepperoni, mozzarella cheese and tomatoes.
In medium bowl, beat eggs with wire whisk. Beat in half-and-half and flour until well blended. Pour over tomatoes; sprinkle with Parmesan cheese.
Return to oven. Bake at 350°F 25 to 35 minutes or until center is puffed and knife inserted in center comes out clean. Sprinkle with parsley. Let stand 10 minutes before serving.