Cook ground beef and onion together until done, drain.
While ground beef is cooking, mix tomatoes and all the spices together.
Add sauce, mushrooms and pepperoni to meat mixture. Let simmer for 10 minutes.
Cut off the top 1/3 of the rolls and hollow out bottoms. Sprinkle 1/2 oz. of cheese in the bottom of each roll. Top with meat mixture. Sprinkle with an additional 1/2 oz of cheese.
Replace tops of rolls. Wrap each sandwich individually in foil and bake on a baking pan for 15 minutes at 375.