Brown the Beef. Start by browning the lean ground beef in a skillet. Crumble it as it cooks, and drain any excess fat. You can skip this step and crumble the uncooked ground beef directly into the slow cooker if you use extremely lean ground beef.
Sauté Onions and Garlic. In the same skillet, sauté chopped onions and minced garlic until they become fragrant and translucent.
Combine Ingredients in the Crockpot. Transfer the browned beef, sautéed onions and garlic, diced tomatoes, tomato sauce, taco seasoning, canned black beans, drained canned corn, and beef broth to your Crockpot. Give everything a good stir to ensure all the flavors meld.
Slow Cook to Perfection. Set your slow cooker to low heat and let the magic happen. Allow the Crockpot Taco Soup to simmer for 6-8 hours or until you can't resist the aroma any longer.
Serve with Toppings. When it's time to serve, ladle the piping hot soup into bowls. Invite everyone to customize their bowls with their preferred taco toppings. Try cheese, sour cream, avocado, and tortilla chips.