In a large pot, add the beef and cook over medium-heat for a few minutes. Add onions and bell peppers and sauté 3 minutes, or until softened. Drain any grease, then stir in taco seasoning and garlic powder. Salt and pepper, to taste.
Addr in black beans, kidney beans, pinto beans, if using, corn, tomato sauce, Rotel, diced tomatoes, and salsa until combined.
Simmer, stirring occasionally, 20 to 40 minutes, or longer if time allows. Add 1/2 to 1 cup warm water if starts to thicken. Stir in cilantro. Salt and pepper, to taste.
Ladle into bowls and top with desired toppings. We love to serve with tortilla chips.
Notes
Topping: If you have a little bit of time, I recommend topping the soup with homemade tortilla strips. Or dip it with tortilla chips or fritos. Crockpot version: Brown beef, onions, and bell peppers in a skillet first. Add all ingredients to the crockpot and cook on low 6 to 7 hours, or on high 3 to 4 hours.Storage: Store leftovers in a covered container in the refrigerator for up to 3 days.To freeze: Let soup cool completely. Place in a zip-top bag or freezer container (leaving room for it to expand). Store in freezer up to 6 months. To thaw, place in refrigerator overnight or microwave. Simmer in a pot over low-heat until warm.