"Threw this together one night to use up some leftovers and knew after the first taste that I'd make it again repeatedly! I love that it's really easy to adjust ingredients to taste and use what's available in the pantry/fridge currently. I've also added sweet potatoes and cabbage and increased the vegetable broth for a more stew-like meal or to change up the leftovers. I would have also added peppers if I'd had them!"
Heat olive oil in a large pot over medium heat. Add onion and mushrooms; cook and stir until softened, 3 to 5 minutes. Pour in tomato juice and vegetable broth. Stir in corn, rice, black beans, tomato, black olives, taco seasoning, and cilantro. Simmer soup until flavors combine, 20 to 30 minutes.
Ladle soup into serving bowls. Garnish each bowl with 1 avocado half.