Remove crusts from bread with a serrated knife. Roll and flatten each bread slice with a rolling pin. Cut 3 circles out of each bread slice with a 1 3/4-inch fluted or round cookie cutter.
Brush mini muffin pans with melted butter. Press bread circles on bottom and up sides of muffin cups; brush bread cups with melted butter.
Bake at 350° for 7 minutes or until lightly toasted.
Remove bread cups from muffin pans, and place on ungreased baking sheets. Fill cups evenly with cheese pieces; top each with 1/4 teaspoon jam.
Bake at 300° for 10 minutes or until cheese is melted.
Note: To make ahead, freeze toasted bread shells up to 1 month in advance. Thaw at room temperature about 30 minutes. Assemble tartlets, and bake as directed.