In a large mixing bowl, combine flour, sugar, baking powder, and salt.
In a smaller bowl, stir together the milk, egg yolks, and butter. A little at a time, add to the flour mixture, beating until smooth.
Add apple and stir. Fold in the egg whites.
Pour ½ cup of batter onto a preheated, greased griddle. Cook until bubbly, then turn and cook the opposite side until golden.
Adapted from Wonderful Good Cooking from Amish Kitchens by Larry Rogers
Add the flavor and nutrition of apples to your next batch of pancakes.