Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
Add the egg whites, nonfat Greek yogurt, half of the banana, ground cinnamon, vanilla extract, baking powder, and sea salt to the blender with the oat flour.
Process the mixture until the batter is smooth and well-combined.
Slice the remaining half of the banana into thin, even rounds.
Heat a large non-stick skillet over medium-low heat and add the coconut oil, swirling to coat the surface evenly.
Pour the batter into the skillet to form three or four small pancakes, then gently press the banana slices into the wet tops of each pancake.
Cook for 3 to 4 minutes until bubbles form on the surface and the edges look set.
Carefully flip the pancakes and cook for an additional 2 minutes, allowing the banana slices to become deeply golden and caramelized against the pan.
Transfer to a plate and serve immediately while warm.