In a high-speed blender, combine the egg, egg whites, almond milk, oat flour, sea salt, and vanilla extract, blending until the mixture is completely smooth and aerated.
Allow the batter to sit for at least 5 minutes; this crucial step lets the oat flour hydrate, ensuring your crepes are flexible and do not tear.
Lightly coat a large non-stick skillet with avocado oil and set over medium heat until a drop of water sizzles on the surface.
Pour roughly 0.25 cup of batter into the center of the pan, immediately tilting and swirling the skillet in a circular motion to spread the batter into a thin, translucent circle.
Cook for 60 to 90 seconds until the edges begin to crisp and pull away from the pan, then carefully flip with a thin spatula.
Sear the second side for an additional 30 seconds until lightly spotted, then transfer to a plate and repeat with the remaining batter.
In a small mixing bowl, fold the fresh lemon zest into the Greek yogurt to create a bright, citrusy filling.
Spread a generous tablespoon of the yogurt mixture down the center of each crepe, top with a handful of berries, drizzle with maple syrup, and roll tightly.