1. Add olive oil to a Dutch oven, or medium pot-and saute the onion (about 4 minutes). Add garlic, chili powder, cayenne pepper, and saute for 1 minute more.
2. Stir in broth, diced tomatoes, beans, and black pepper
3. Bring to boil. Turn down heat to low, and let simmer for 15 minutes.
4. If using corn-you can add this now.
5. Let soup simmer for another 5 minutes.
Directions for the Tortilla Strips. Add olive oil to a heavy skillet. Heat oil over medium heat. Add the tortilla strips (in batches) and fry until golden brown. Remove with a slotted spoon. Place on paper towels to drain.
6. Add ½ of the tortilla strips to the soup. Let simmer for 5 more minutes.
Serve soup with the remaining tortilla strips, slices of avocado, lime wedges, shredded cheese (I use Kraft’s Mexican Blend), and sour cream.