In a large bowl, combine the Quick Bread Mix and cinnamon and set aside.
In a 2 cup glass measuring cup, combine the milk, sour cream, and egg yolk.
Add to the dry ingredients all at once and stir just until moistened (the batter will be lumpy).
Fold in the apple.
In a small bowl, beat the egg white until it holds stiff, dry peaks; fold into the batter.
Do not overmix; a few small puffs of egg white should be visible in the batter.
Lightly coat a heavy 12 inch skillet with the cooking spray and set over moderate heat.
Using about 4 cup batter per pancake, pour in the batter, 2 or 3 portions at a time, and cook for 1 to 2 minutes or until bubbles form on the pancakes.
Turn and brown 1 to 2 minutes more.