Combine flour, oats, baking powder, sugar and pecans in a large bowl.
Combine egg yolks, milk and vegetable oil in a separate bowl, and mix well.
Add liquid mixture to the dry ingredients, and stir together. Do not over mix; mixture should be a bit lumpy.
Whip egg whites into medium peaks. Gently fold egg whites into batter (for pancakes, see note below).
Pour batter into preheated waffle iron, and cook until the waffle iron light signals it's done or steam stops coming out of the iron. (A waffle is perfect when it is crisp and well-browned on the outside with a moist, light, airy and fluffy inside).
Add fresh fruit and a light dusting of powdered sugar to each waffle and serve.
For pancakes, do not separate eggs. Mix whole eggs with milk and oil, and eliminate steps 4 and 5.