In a medium bowl, whisk together the egg whites, Greek yogurt, and vanilla extract until the mixture is smooth and well combined.
Stir in the oat flour, vanilla protein powder, ground cinnamon, baking powder, and sea salt until a thick, uniform batter forms.
Slice the half banana into thin, even rounds.
Heat the coconut oil in a large non-stick skillet over medium-low heat until shimmering.
Place 3 to 4 banana slices into the pan for each pancake, then carefully pour the batter directly over the slices.
Cook for 3 to 4 minutes until bubbles begin to form on the surface and the edges look set, then flip carefully with a wide spatula.
Cook for another 2 minutes until the pancakes are cooked through and the bananas have developed a deep golden caramelized finish.
Serve the pancakes immediately while warm, perhaps topped with an extra dollop of Greek yogurt.