Blend rolled oats in a blender or food processor for 30 to 45 seconds until they resemble a fine flour with no visible oat pieces. Set aside.

In a medium mixing bowl, combine oat flour, liquid egg whites, Greek yogurt, vanilla extract if using, and salt. Whisk until completely smooth with no lumps.

Let the batter rest for 5 minutes so the oat flour absorbs the moisture and thickens the batter slightly. Do not skip this step.

Heat a non-stick skillet over medium-low heat. Lightly grease with cooking spray or a small amount of coconut oil. Pour about 1/4 cup of batter into the center and immediately swirl the pan to spread into a thin even round. If batter is too thick to swirl, add a small splash of water and whisk before continuing.

Cook for 1 minute to 1 minute 30 seconds until the edges lift easily on their own and the surface looks fully set. Flip carefully and cook for another 30 seconds. Transfer to a plate, cover loosely with foil, and repeat with remaining batter.