Berrieswhipped cream and maple syrup, for serving, if desired
Preheat waffle iron according to manufacturer's directions.
In a large bowl, whisk together the all-purpose flour, whole wheat flour, baking powder, baking soda, salt, and brown sugar. If you have any brown sugar clumps, use your clean hands to unclump the sugar and whisk again.
In a medium bowl, beat together eggs and melted butter. Stir in the buttermilk and vanilla extract.
Add the wet ingredients to the dry ingredients and stir until just combined. Don't overmix.
Spray the waffle with nonstick cooking spray. Pour the recommended amount of waffle batter onto the hot waffle iron. Close the waffle iron and cook until the waffle is golden on both sides and is easily removed from iron. Serve immediately or keep warm in a 200 degree F oven until ready to serve.