Place the rolled oats in a high-speed blender and pulse until they reach a fine, flour-like consistency.
In a large mixing bowl, mash the three ripe bananas with a fork until mostly smooth with only small lumps remaining.
Whisk the egg whites, non-fat Greek yogurt, and vanilla extract into the mashed bananas until the mixture is well combined.
Stir in the oat flour, baking powder, ground cinnamon, and sea salt until a thick, uniform batter forms.
Heat the avocado oil in a large non-stick skillet or griddle over medium-low heat to ensure even cooking.
Pour approximately 1/4 cup of batter per pancake onto the hot skillet, cooking for 3 to 4 minutes until bubbles form on the surface.
Carefully flip the pancakes and cook for an additional 2 to 3 minutes until the centers are set and the exterior is golden brown.
Serve the warm pancakes immediately, optionally garnished with a sprinkle of extra cinnamon or a dollop of yogurt.