Preheat the waffle iron on the highest heat setting.

In a medium size bowl, combine the unbleached all purpose flour, baking powder, baking soda, and kosher salt. Whisk well to combine.

In a large mixing bowl, combine the sourdough discard (unfed sourdough starter), milk, granulated sugar, yogurt, egg. Whisk very well to combine, especially to ensure that the sourdough discard is thoroughly incorporated.

Slowly stream in the melted butter into the wet ingredients, whisking while you pour, until the butter is well mixed in.

Add the dry ingredients to the large bowl with the wet ingredients. Whisk gently until just combined, leaving just a few lumps in the batter.

Use nonstick cooking spray to coat the top and bottom plates of the waffles iron. Each waffle iron is different, but pour roughly ¼ cup of batter into each section of the waffle iron. Cook for 4 minutes until the waffles are golden brown, and crispy.

Serve the waffles with plenty of soft salted butter, real maple syrup, and berries.