In a large bowl, combine all of the dry ingredients: add the all-purpose flour, cornmeal, sugar, baking soda, baking powder, and sea salt, and mix well.
Using a separate bowl, add two whole eggs and one egg yolk and beat well.
Add the buttermilk, melted butter, and pure vanilla extract to the eggs and continue to mix well.
Little by little, add the wet ingredients to the dry ingredients and mix until the mixture is just combined. Overbeating will result in tough pancakes, and who wants that?
Cover the pancake batter with a large dish towel and let it sit for 10 minutes.
Place a large cast-iron skillet over low-medium heat, add two tablespoons of melted butter, or use canola or vegetable oil.
When the skillet is hot, add two and a half (2 1/2) tablespoons of pancake batter and use a spoon to spread the batter into a circle.
Watch the pancake closely. When small air bubbles start to appear on the surface, flip the pancake over and cook until golden brown.
When finished, add a bit of melted butter and store pancakes in a warm oven until they're all done.
Add your favorite toppings, like yogurt, fruit, traditional maple syrup, or bourbon barrel-aged maple syrup.
Serve and enjoy.