Turn oven on to 425*. Place a 9-10 inch cast iron skillet into the oven while it is preheating.
Into a large bowl, combine plant milk, water, canola oil, maple syrup, lemon juice, and flax. Whisk to combine.
Add the cornmeal to the liquids and whisk to combine. Set aside.
Add 1 tablespoon of plant butter into the preheating skillet. Leave in the oven to melt.
In a small bowl, combine white whole wheat flour, baking powder, baking soda and salt.
Add the dry ingredients into the cornmeal mixture. Whisk to combine.
The oven should be heated to 425* by now, so using an oven mitt and working carefully, remove the skillet and swirl the melted plant butter around to coat the pan.
Immediately pour cornbread batter into the skillet. It should sizzle as it hits the hot skillet. Place skillet back into the oven and bake for 30 minutes or until a tooth pick inserted into the center comes out clean.
Let cool for at least 30 minutes before serving.