Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
In a medium mixing bowl, whisk together the oat flour, vanilla protein powder, baking powder, ground cinnamon, and sea salt until well combined.
Add the egg whites, half of the Greek yogurt (0.25 cup), and vanilla extract to the dry ingredients, stirring until a smooth, thick batter forms.
Peel the half banana and cut it into thin, even rounds.
Heat a large non-stick skillet over medium heat and add the ghee, swirling to coat the surface evenly.
Place the banana slices directly onto the hot skillet in small clusters, then pour the pancake batter over each cluster to form three or four pancakes.
Cook for 2-3 minutes until bubbles form on the surface and the edges look set, then carefully flip to cook the other side for another 2 minutes until the bananas are golden and caramelized.
Transfer the pancakes to a plate and top with the remaining 0.25 cup of Greek yogurt before serving.