In large stockpot, brown ground beef over medium heat. Add onions and peppers and cook for 4–5 minutes. Add garlic and cook for additional 60 seconds.
Stir in cumin, oregano, paprika, chili powder, onion powder, brown sugar and cayenne pepper. Reserve 1 cup black beans and set aside. Stir in remaining black beans, diced tomatoes and beef broth. Simmer for 10 minutes.
Mix tomato paste with 1/4 cup of the hot broth. Stir into the soup.
Run the reserved black beans through a food processor or mash them with a traditional potato masher. Stir them into the soup. Simmer for 20 minutes.
If desired, top with sour cream, shredded cheddar and green onions.