In a large mixing bowl, whisk together the liquid egg whites, nonfat Greek yogurt, oat flour, baking powder, sea salt, and vanilla extract until the batter is smooth.
Core the apple and slice it into thin wedges.
Heat a large non-stick skillet over medium heat and add half of the ghee to melt.
Add the apple slices, cinnamon, and nutmeg to the skillet, sautéing for 5-7 minutes until the apples are soft and golden brown.
Remove the caramelized apples from the skillet and set them aside on a plate.
Wipe the skillet clean and add the remaining ghee.
Pour the pancake batter into the skillet to form 3-4 small pancakes.
Cook for 3-4 minutes until bubbles appear on the surface and the edges look set.
Carefully flip the pancakes and cook for another 2-3 minutes until golden brown on the bottom.
Plate the pancakes and top them immediately with the warm caramelized apples.