Preheat the waffle maker.
In a large bowl, whisk the flour, cornmeal, sugar, sea salt, and baking soda together.
In a separate bowl, whisk together the egg yolks and melted butter. Then add the buttermilk to that mixture.
In a third bowl, beat the egg whites and cream of tartar with an electric mixer on medium-high speed until soft peaks form.
Pour the buttermilk mixture into the large bowl with dry ingredients, and gently whisk until just incorporated (some lumps should remain). Then fold the whipped egg whites into the batter.
Spray the waffle maker with cooking spray to keep waffles from sticking.
Pour the prepared batter onto the waffle maker and cook through, about 3 minutes per waffle. (I use a measuring cup to measure out 1 cup of batter at a time and then pour it over the waffle maker) *You can keep waffles warm in a 200-degree oven or serve one at a time.