Combine first 5 ingredients in a medium bowl; make a well in center of mixture. Combine buttermilk, oil, and egg white, stirring with a wire whisk. Add to dry ingredients, stirring just until dry ingredients are moistened.

Coat an 8-inch square waffle iron with cooking spray; allow waffle iron to preheat. Pour batter onto hot waffle iron, spreading batter to edges. Bake 3 to 4 minutes or until steaming stops. Cut waffle into 4 squares. Serve with fresh strawberries, if desired.