Preheat your oven to 375°F (190°C).
In a high-speed blender, combine the rolled oats, egg whites, 0.25 cup of the Greek yogurt, vanilla protein powder, vanilla extract, baking powder, and sea salt.
Blend on high until the mixture is completely smooth and resembles a thick pancake batter.
Core and thinly slice the apple into uniform wedges.
Heat the ghee in an 8-inch oven-safe skillet over medium heat.
Add the apple slices and ground cinnamon to the skillet, sautéing for 3-4 minutes until the apples are slightly softened and fragrant.
Arrange the apples in an even layer across the bottom of the skillet.
Pour the batter evenly over the apples, ensuring they are fully covered.
Transfer the skillet to the oven and bake for 12-15 minutes, or until the center is set and the edges are golden brown.
Carefully remove from the oven and top with the remaining 0.25 cup of Greek yogurt before serving.