If you are planning to serve all the pancakes at once, preheat your oven to 200°F to keep the pancakes warm between batches.
Separate out egg whites from yolks, dropping the whites into a small mixing bowl and reserving the yolks in any small container to use later in the recipe. Set both aside.
In a medium bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In a separate, large bowl, combine buttermilk, the egg yolks, melted and slightly cooled butter, and vanilla. Whisk until smooth.
Pour the flour mixture into the bowl of wet ingredients and stir until just mixed and there is no dry flour at the bottom of the bowl. The batter will look very thick at this point.
Use a handheld electric mixer starting on low and working up to high to beat the egg whites until stiff peaks form (when beaters are lifted out, the whites should stand straight up without curling over at the tips or collapsing)
With a rubber spatula, gently fold the egg whites into the batter. Do not over-mix or you risk deflating the egg whites.
Fold in the chocolate chips.
Heat an electric griddle to 325°F or a large skillet over medium heat.
Once your cooking surface is hot, lightly grease it with cooking spray or butter. Evenly space out slightly heaping ⅓ cups of batter. Cook until bubbles begin to form on the tops of the pancakes and and then flip and cook until done.
If needed, place the pancakes on a cookie sheet in the oven to keep them warm. Repeat with remaining batter.
Add your favorite toppings, serve, and enjoy!