This recipe is assembled the day it's served. Put sauce in a 3-cup container, cheeses in 2-1 quart bags, pepperoni in 1-quart bag; wrap bread in heavy foil. Freeze.
To Serve: Thaw French bread, sauce, grated cheeses and pepperoni. Slice loaf of French bread in half lengthwise. Layer sauce. Parmesan cheese, pepperoni and mozzarella cheese on each half. Set oven to broil and/or 550 degrees F. Place bread on baking sheet, and put in the oven. Broil until mozzarella is melted. Cut into serving size pieces.