Preheat oven to 425Â°.
Combine first 6 ingredients in a bowl; make a well in center of mixture.
Combine buttermilk, oil, and egg whites in a bowl; stir well.
Add to dry ingredients, stirring just until moist.
Divide batter evenly among 15 muffin cups coated with cooking spray.
Bake at 425Â° for 12 minutes or until golden.
Remove muffins from pans immediately.