In a large pot or Dutch oven over medium-high heat, add the ground beef, diced onion, bell pepper, and garlic. Cook until the beef is fully browned and the vegetables are softened. Drain any excess grease from the pot to keep the chili from becoming too oily.
Stir in the chili powder, cumin, crushed tomatoes, kidney beans, and beef broth. Bring the mixture to a gentle boil, then reduce the heat to low. Cover and let the chili simmer for at least 20 to 25 minutes, stirring occasionally to prevent sticking.
While the chili is simmering, preheat your oven to 400°F (200°C). In a medium bowl, whisk together the cornmeal, flour, sugar, baking powder, and salt. In a separate small bowl, whisk the milk, egg, and melted butter. Combine the wet and dry ingredients, stirring just until moistened.
You can bake the cornbread in a separate greased 8×8 inch pan for 20 minutes, or for a “chili pie” style, pour the batter directly over the simmering chili in an oven-safe pot and bake until the cornbread is golden brown and a toothpick comes out clean.
Once the cornbread is done, remove it from the oven and let it sit for 5 minutes. This allows the chili to thicken slightly and the cornbread to set, making it much easier to slice and serve.