01 - Heat olive oil in a large skillet over medium-high heat. Brown beef cubes in batches, transferring each batch to the slow cooker as completed.
02 - In the same skillet, sauté diced onion and bell peppers for 4 minutes until softened. Add minced garlic and cook for an additional minute.
03 - Incorporate chili powder, ground cumin, smoked paprika, dried oregano, cayenne pepper (if using), salt, and black pepper. Cook for 1 minute until aromatic.
04 - Stir in tomato paste and cook for 2 minutes. Transfer this mixture to the slow cooker.
05 - Add crushed tomatoes, kidney beans, black beans, beef broth, and brown sugar to the slow cooker. Stir thoroughly to combine all components.
06 - Cover and cook on low for 7-8 hours or on high for 4 hours, until beef is tender.
07 - Preheat oven to 400°F. In a mixing bowl, whisk together cornmeal, all-purpose flour, granulated sugar, baking powder, and salt. In a separate bowl, whisk milk, eggs, and melted butter. Add wet ingredients to dry and mix until just combined. Fold in shredded cheddar cheese and diced green chilies if desired.
08 - Remove slow cooker insert if oven-safe, or transfer chili to a baking dish. Spread cornbread batter evenly over chili surface. Bake in the preheated oven for 25-30 minutes, until cornbread turns golden and a toothpick inserted comes out clean.
09 - Allow to rest for 10 minutes before serving to let flavors meld and topping set.