Preheat oven to 350˚F/180˚C. Lightly grease a 9x9 inch baking dish. In a small bowl, stir together 1 tablespoon of flax meal with 2 ½ tablespoons of water. Let sit for 10 minutes, until the flax absorbs the water.
In a large mixing bowl, stir together cornmeal, gluten free flour, baking powder, baking soda, salt and remaining 1 tablespoon of flax meal.
In a separate bowl, whisk together milk, maple syrup, flax "egg" (flax + water), lemon juice and melted butter.
Using a spatula, stir the wet ingredients into the dry ingredients until combined. Don't overmix the batter – just whisk until there are no big lumps of flour. The less mixing, the fluffier your cornbread will be!
Let the batter sit for 15 minutes, then pour into prepared baking dish.
Bake for 33-36 minutes until golden brown and a toothpick inserted into the center comes out clean. Remove from oven and let cool before slicing. If you slice it too soon, it will be pretty crumbly.