Place beef, broth, soy sauce, garlic, and 1/2 of the peppers and 1/2 the onions in the slow cooker.

Cook on low about 8 hours.

Add remaining onions and peppers and cook for another hour.

Preheat oven to 350.

Open sub rolls and place provolone on each side and heat until cheese is melted and bread is slightly crunchy.

Top with meat mixture and serve.