01 - Heat a large skillet over medium-high heat. Brown the beef in batches to develop rich flavor, draining excess fat as needed. If using ground beef, cook until browned, breaking up the meat.
02 - Add the browned beef to a 6-quart or larger slow cooker.
03 - Add diced onion, red bell pepper, minced garlic, and jalapeño to the slow cooker with the beef.
04 - Pour in crushed tomatoes, diced tomatoes, and tomato paste. Add kidney beans, black beans, chili powder, cumin, smoked paprika, oregano, cayenne, salt, black pepper, and beef broth. Stir thoroughly to distribute all spices evenly.
05 - Cover and cook on low for 6-8 hours or on high for 4 hours, until beef is very tender and flavors have fully melded together.
06 - Taste the chili and adjust salt, pepper, or cayenne as desired before serving.
07 - Ladle hot chili into bowls and top with shredded cheddar cheese, sour cream, chopped cilantro, or sliced green onions as desired.