01 - In a large skillet over medium heat, cook ground beef until no longer pink, breaking into crumbles, about 5 to 7 minutes; drain excess fat if necessary.
02 - Place the cooked ground beef into the slow cooker container.
03 - Incorporate chopped onion, diced bell pepper, minced garlic, and jalapeño if using into the slow cooker.
04 - Add kidney beans, black beans, crushed tomatoes, diced tomatoes with their juice, and beef broth to the slow cooker.
05 - Stir in chili powder, ground cumin, smoked paprika, oregano, black pepper, salt, and optional cayenne pepper until evenly mixed.
06 - Cover the slow cooker and cook on LOW for 6 to 8 hours or on HIGH for 3 to 4 hours, stirring occasionally if possible.
07 - Taste the chili and adjust salt or spices as needed before serving.
08 - Ladle into bowls and garnish with shredded cheddar, sour cream, chopped cilantro, and green onions as desired.