Separate the egg white from the yolk. Place the white in a small clean mixing bowl, and the yolk in another small mixing bowl.
Add the protein powder, mashed banana, nut butter and baking soda to the egg yolk. Whisk until a smooth batter forms, then set aside.
Depending on the protein you use, you might find your mixture is very thick at this point. If so, add 2-4 teaspoons of milk of choice or water. It should be roughly the consistency of a medium thickness yoghurt.
Use a hand beater to whip the egg white until stiff peaks form.
Add about 1/3 of the egg white and the vinegar or lemon juice to the protein mixture. Use a spatula to gently fold the egg white into the mix, trying to preserve bubbles while mostly incorporating the whites. The bubbles will help keep your pancakes fluffier and taller.
Add the remaining whites and fold until incorporated.
Preheat a pan on a medium heat, then add a small amount of oil or butter. You can cook the pancakes one at a time or all together (depending how thick your batter is). Cook for 1-2 minutes on the first side or until the top begins to bubble. Flip and cook on the other side for 2 or so minutes or until cooked through. Adjust the heat as necessary.
Repeat with the remaining batter. Serve with yoghurt, fruit, maple syrup or butter.