Blend rolled oats in a blender or food processor until fine to make oat flour.
In a bowl, combine oat flour, whey protein powder, sugar (if using), baking powder, baking soda, and salt. Stir well.
In a separate bowl, whisk together milk, egg whites, vanilla extract, and Greek yogurt until smooth.
Pour dry ingredients into wet ingredients. Stir until just combined (a few lumps are fine). Let batter rest for 5 minutes.
Heat a greased pan or griddle to medium heat. Pour about ¼ cup batter per pancake.
Cook for 2-3 minutes on the first side (bubbles will form). Flip carefully and cook for another 2-3 minutes on the second side.
Serve warm with toppings of your choice.