Heat waffle iron.
Whisk together the flour, salt, baking soda, and cinnamon together in a large mixing bowl, until well combined.
Whisk together the egg yolk, buttermilk, cooled melted butter, and vanilla in a small bowl, until well combined..
In a separate bowl, beat or whisk the egg whites until it just holds a 2-inch peak.
Slowly add the liquid ingredients to the dry ingredients in a thin, steady stream while mixing gently with a rubber spatula.
Side Note: Do not add liquid faster than you can incorporate it into the batter.
Toward the end of mixing, use a folding motion to incorporate the ingredients.
Gently ford the egg white into the batter. Set aside for a few minutes.
Spray the hot waffle iron well with coconut oil cooking spray.
Spread an appropriate amount of batter onto the waffle iron.
Following your waffle iron's instructions, cook the waffle until golden brown, 2-5 minutes.
Serve immediately with butter, syrup, and jam, if desired. Enjoy.