In a medium size bowl, stir together cornmeal, flour, baking powder, salt, and sugar.
In another bowl, beat egg yolks, then stir in oil and buttermilk.
In a third bowl, beat egg whites until soft, moist peaks form.
Add egg yolk mixture to cornmeal mixture, stirring only enough to moisten dry ingredients.
Fold egg whites lightly into batter.
Spoon batter into greased or paper lined muffin pan with 2 1/2 inch diameter cups, filling each about two thirds full.
Bake in a 400°F oven for 20 to 25 minutes or until golden brown.
Turn out onto rack immediately.