In a large pot or Dutch oven, brown the ground beef over medium-high heat, breaking it up with a wooden spoon. Cook until no longer pink, about 8-10 minutes. Drain excess fat.
Add diced onion and bell pepper to the pot. Cook for 5-6 minutes until softened.
Stir in minced garlic and cook for 1 minute until fragrant.
Add chili powder, cumin, smoked paprika, oregano, and cayenne pepper. Stir well to coat the meat and vegetables with spices. Toast for 1-2 minutes to bring out the flavors.
Add crushed tomatoes, tomato paste, beef broth, kidney beans, and pinto beans. Stir everything together.
Stir in brown sugar, salt, and black pepper. Bring the chili to a boil.
Reduce heat to low and simmer uncovered for 1 hour, stirring occasionally. The chili will thicken as it cooks.
Taste and adjust seasonings as needed. For a thicker chili, continue simmering for another 15-30 minutes.
Serve hot topped with shredded cheddar cheese, a dollop of sour cream, and chopped green onions. Don't forget the cornbread!