Heat a large pot over medium heat and add the ground beef. Cook until browned, breaking it up with a spoon as it cooks.

Add the diced onion and minced garlic to the pot. Stir and cook for 3 minutes until the onion softens.

Stir in the chili powder, cumin, salt, and black pepper. Cook for 1 minute to toast the spices.

Pour in the diced tomatoes and kidney beans. Bring the mixture to a gentle simmer, then lower the heat and cook uncovered for 20 minutes, stirring occasionally.

While the chili simmers, preheat the oven to 400°F and grease an 8-inch baking pan.

In a mixing bowl, whisk together the cornmeal, flour, baking powder, and sugar. In a separate bowl, mix the milk, egg, and melted butter. Combine the wet and dry ingredients until just mixed.

Pour the cornbread batter into the prepared pan and bake for 20 minutes until the top is golden and a toothpick comes out clean.

Let the cornbread cool for a few minutes, then cut it into squares and serve alongside bowls of the chili.