Combine flour, sugar, baking powder, baking soda and salt. Sift using a whisk.
In a separate bowl whisk together the buttermilk, melted butter, egg yolks and vanilla.
Add the wet to the dry stirring just until combined.The mixture will be lumpy. Set aside.
Using an electric mixer, beat the egg whites until stiff peaks have formed. Fold into the batter.
Butter a cast iron skillet or griddle and heat to medium-high. Divide the pancake batter using a ¼ cup measuring cup. (May use cooking spray in place of butter, if desired)
Cook until golden and the batter has bubbled on top for around 2 minutes per side, then flip.
Cook in batches adding more butter to the pan as needed. Keep warm until serving.
Serve drizzled with maple syrup and butter.