In a large skillet, brown the ground beef over medium heat. Drain off any excess grease.

Add the chopped onion and minced garlic to the skillet and cook until softened, about 5 minutes.

Stir in the drained kidney beans, diced tomatoes (with their juice), chili powder, cumin, salt, and pepper. Bring to a simmer and cook for 10-15 minutes, or until the sauce has thickened.

If using, stir in the shredded cheddar cheese until melted. Set aside to cool slightly.

Preheat your oven to 375°F (190°C). Grease and flour a 12-cup muffin tin, or line with paper liners.

In a large bowl, whisk together the flour, cornmeal, sugar, baking powder, baking soda, and salt.

In a separate bowl, whisk together the milk, vegetable oil, and eggs.

Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.

Spoon about 1 tablespoon of corn muffin batter into the bottom of each muffin cup.

Spoon about 1-2 tablespoons of the chili filling into the center of each muffin cup, on top of the batter.

Top with another tablespoon of corn muffin batter, ensuring the chili is mostly covered.

Bake for 20-25 minutes, or until a toothpick inserted into the corn muffin portion comes out clean.

Let the muffins cool in the tin for a few minutes before transferring them to a wire rack to cool completely.