01 - Heat a large skillet over medium heat. Add the ground beef and diced onion, breaking up the meat with a spoon. Cook until the beef is no longer pink, approximately 6-8 minutes. Drain any excess fat.
02 - Add the cooked beef and onion mixture to the bottom of a 6-quart slow cooker, spreading it evenly.
03 - Arrange the diced potatoes, kidney beans, corn, and diced tomatoes in layers over the beef mixture in the slow cooker insert.
04 - In a medium bowl, whisk together the condensed mushroom soup, beef broth, smoked paprika, garlic powder, dried oregano, black pepper, and salt until smooth and well combined.
05 - Pour the soup mixture evenly over all the layered ingredients in the slow cooker, ensuring coverage across the top.
06 - Cover the slow cooker with its lid. Cook on LOW setting for 6 hours, or until the potatoes are completely tender when pierced with a fork.
07 - During the final 15 minutes of cooking, sprinkle the shredded cheddar cheese evenly over the top of the casserole. Cover and allow the cheese to melt completely.
08 - Spoon hot portions into bowls. Garnish with fresh chopped parsley or sliced green onions if desired. Serve immediately while hot.