In a large mixing bowl, whisk together the Greek yogurt, lemon juice, egg whites, whole egg, and vanilla extract until the mixture is completely smooth.
Add the oat flour, vanilla protein powder, baking powder, and sea salt to the wet ingredients and fold gently with a spatula until no dry streaks remain.
Preheat a large non-stick griddle or skillet over medium-low heat and lightly brush the surface with the avocado oil.
Scoop 1/4 cup portions of batter onto the hot surface, leaving at least two inches of space between each pancake to allow for spreading.
Cook for 3-4 minutes until the edges appear set and small bubbles begin to form on the surface, then flip carefully.
Cook for an additional 2 minutes on the second side until the pancakes are fluffy, cooked through, and golden-brown.