In a large pot, over medium heat, add the ground beef. Break it apart with a wooden spoon and cook until it’s nicely browned. Drain any excess fat.

Add the chopped onion to the pot with the beef. Sauté for about 3-4 minutes until the onion is translucent. Stir in the minced garlic and cook for an additional minute.

Sprinkle in the chili powder, cumin, and add salt and pepper to taste. Stir well to ensure seasonings coat the meat and vegetables evenly.

Pour in the drained kidney beans, black beans, and diced tomatoes with their juices. Stir together and bring to a gentle simmer. Let it cook for 20-30 minutes, stirring occasionally.

While the chili simmers, preheat your oven to 400°F (200°C). Grease a muffin tin or use muffin liners.

In a mixing bowl, combine the cornmeal, all-purpose flour, baking powder, and sugar. Whisk until well mixed.

In another bowl, whisk together the milk, eggs, and vegetable oil until combined.

Pour the wet mixture into the bowl of dry ingredients and gently stir until just combined. Be careful not to overmix.

Scoop the batter into the prepared muffin tins, filling each cup about two-thirds full.

Bake in the preheated oven for 15-20 minutes or until golden brown. Serve the chili hot with cornbread muffins on the side.