01 - Heat olive oil in a large pot over medium heat. Add ground beef and cook until browned, breaking it apart with a spoon, approximately 5 to 7 minutes. Drain excess fat if necessary.
02 - Add diced onion, red bell pepper, and minced garlic. Sauté until vegetables are softened, about 5 minutes.
03 - Incorporate diced pumpkin into the pot and cook for an additional 3 to 4 minutes.
04 - Stir in tomato paste, chili powder, ground cumin, smoked paprika, ground cinnamon, salt, black pepper, and cayenne pepper if desired. Coat the beef and vegetables evenly with the spice blend.
05 - Pour in diced tomatoes with their juice, black beans, kidney beans, and broth. Bring the mixture to a boil, then reduce heat and simmer uncovered for 30 to 35 minutes, stirring occasionally until pumpkin is tender and chili is thickened.
06 - Adjust salt, pepper, and spices to taste as needed.
07 - Ladle chili into ovenproof bowls. Top each serving with shredded cheddar cheese arranged in a web pattern using a piping bag or by forming concentric circles with intersecting lines.
08 - Place bowls under a preheated broiler for 2 to 3 minutes, or until cheddar cheese is melted and bubbling. Serve immediately while hot.