1. Stir together first 6 ingredients in a large bowl. Whisk together buttermilk and next 4 ingredients in a medium bowl. Stir buttermilk mixture into flour mixture. Stir in chocolate.
2. Preheat waffle iron, and coat with cooking spray. Ladle about 1/3 cup batter onto hot iron, spreading to edges. Cook 3 to 4 minutes or until waffle is golden brown and steaming stops. Repeat with remaining batter. Garnish, if desired.