3. Make the Batter
In a large bowl, whisk together the cornmeal, flour, baking powder, baking soda, and salt. In a medium bowl, whisk together the sour cream, water, the remaining 1/2 cup of sugar, and the eggs. Add the sour cream mixture to the cornmeal mixture, drizzle with the melted butter, and stir until just combined. Pour the batter into the prepared cake pan and smooth the top with a rubber spatula.