Preheat pancake griddle to 400° F.
Sift flour into large mixing bowl. Add powdered sugar. Add baking powder. Add vanilla extract. Add sour cream. Add three eggs yolks. Add buttermilk.
In a separate bowl, beat egg whites into a meringue and set aside. Mix ingredients of large bowl until ingredients are well mixed with no lumps.
If necessary, add a little more buttermilk just until batter pours out of a large spoon or drips off the mixer beaters continuously, not in lumps.
Fold in the egg white meringue. Test the pancake griddle for the proper heat. Lightly spray griddle with Pam cooking spray.
Quickly spoon batter out to make eight 3 to 4 inch pancakes.
Allow pancakes to cook until golden brown, about 30 to 60 seconds, then flip.Makes 3 to 4 Source: