Butter a deep-sided 9x13-inch lasagna or casserole pan. Preheat oven to 400 degrees F.
In a large mixing bowl whisk the flour, cornmeal, baking powder and salt together. Mix in 1 cup of the cheddar and the onion.
In a separate medium bowl whisk the eggs, milk, butter and sour cream together. Add this mixture to the dry mix and stir together just until combined.
Spoon the chili into the baking pan (*for the extra cheesy version sprinkle with 1 cup of cheese). Drop spoonfuls of the cornbread mixture over top and gently spread it out. Sprinkle with the remaining cup of cheese.
Bake 20 - 22 minutes or until a toothpick comes out clean from center of cornbread. Let set for 5 -10 minutes before slicing. Serve with a dollop of sour cream.