Place the ground beef, onion, garlic, kidney beans, crushed tomatoes, chili powder, cumin, and salt in the crockpot. Stir everything together until the spices are evenly distributed.
Cover and cook on low for 6 to 8 hours until the beef is fully cooked and the chili has thickened.
About 30 minutes before serving, heat the oven to 400 degrees. In a mixing bowl combine the cornmeal, flour, baking powder, milk, egg, and melted butter. Stir just until a batter forms.
Spread the batter in a lightly greased 8-inch baking pan and bake for 15 to 18 minutes until the edges are golden. Let it cool slightly, then break it into coarse crumbles.
Ladle the chili into bowls and scatter the warm cornbread crumbles over each serving.