Add to a bowl Greek yogurt, egg, egg whites, maple syrup (or preferred sweetener), apple cider vinegar (optional), ground cinnamon and vanilla extract. Stir to get a creamy mixture.
Sift in oat flour (or any flour of your choice), protein powder and baking powder. Stir to combine. Depending on the protein powder that you are using, your batter may require a bit of milk (see notes*).
Stir chopped apple into the protein pancakes batter.
Pour one scoop of pancakes batter into a hot and greased pan. Cook your pancakes over medium heat until the underside is golden and bubbles begin to appear on the surface, then flip with a spatula and cook until golden.