Add onion, garlic, tomato paste, whole jar pepperoncini with juice, jalepeno pepper, brown sugar, and cumin in a blender or food processor. Turn on high and blend until everything is combined and it's the consistency of an onion shake! Pour over beans in crock pot, scraping sides of blender bowl with a spatula to get all the goodies out and in with the beans. Pour broth in with the beans. Cover and cook on high setting for 6 hours. Stir occasionally if you can.