Preheat the oven to 375 degrees. Use coconut oil to liberally grease a 9 x 9″ pan.
In a large bowl, whisk together the cornmeal, flour, baking powder, baking soda, kosher salt, and sugar.
Whisk together the almond milk and apple cider vinegar in a liquid measuring cup. Melt the coconut oil, then pour both the almond milk and coconut oil into the dry ingredients. Stir until just combined. Pour into the prepared pan.
Bake about 30 minutes until the center has firmed up and a toothpick comes out clean. Allow to cool in the pan completely, about 30 minutes. Then run a knife around the edges and invert. Cut into 16 squares and serve. Store any leftovers at room temperature covered with a towel for about 3 days, or in a sealed container at room temperature for about 5 days.