Trim ends from French bread. Cut crosswise into 16 equal slices. Arrange slices in a single layer on a 14- by 17-inch baking sheet.
Bake in a 350° oven until lightly browned, about 25 minutes. Let cool to room temperature, about 10 minutes. Put 1/2 the slices in each of 2 plastic freezer bags (1-gal. size). Seal bags and freeze (see Cold Facts below).
To serve 4, remove frozen toasts from 1 bag and lay in a 10- by 15-inch pan. Cut cheese into 1/4-inch-thick slices. Cover toasts evenly with cheese.
Bake in a 400° oven until cheese melts, 8 to 10 minutes.
Cold Facts. Packaging: freezer bags. Squeeze out all air and seal bag. For better protection of frozen foods during storage, seal each bag inside a second one. Lay bags flat in freezer until solid so they will stack.