Preheat the oven to 375°F. Lightly grease a 9" x 9" square pan., Whisk together the cornmeal, King Arthur Gluten-Free All-Purpose Flour, buttermilk powder, Cake Enhancer, baking powder, salt, xanthan gum, and baking soda., Whisk together the melted butter or oil, sugar, water, vinegar, and eggs., Stir in 1 cup of the dry ingredients. Add the remaining dry ingredients about 1 cup at a time; after each addition, scrape the bottom and sides of the bowl, and beat for 30 seconds on medium-high speed., Once all the dry ingredients have been added, beat on medium speed for an additional 2 to 3 minutes., Spoon the batter into the prepared pan. Use your wet fingers to gently smooth the surface. Let the cornbread sit for 10 minutes., Bake the cornbread for 25 to 30 minutes, until it's golden brown, about 3 to 4 minutes beyond the point where a toothpick inserted into the center comes out clean. The internal temperature of the finished bread should be 190°F., Remove the bread from the oven, cool 5 minutes, and serve warm.