Preheat waffle iron.
In a large bowl, whisk together the flour, baking powder, sugar and salt until combined. Set aside.
230 grams all-purpose flour, 50 grams sugar, 12 grams baking powder, 3 grams salt
In a liquid measuring cup, heat the milk in the microwave until warm, not hot.
320 grams warm milk
To a medium bowl, add the melted butter, warm milk, eggs, room temperature, sourdough discard and vanilla extract. Whisk until smooth.
2 eggs, 100 grams sourdough discard, 113 grams unsalted butter, melted, 8 grams vanilla extract
Pour the wet ingredients into the dry ingredients and whisk until blended. Careful not to over mix, a few lumps in the batter is okay! Allow the batter to rest for at least 10-15 minutes.
Spoon batter and pour into the hot waffle iron and cook until golden brown and crisp. (Refer to your waffle maker's instruction for how much sourdough waffle batter will fit. Mine fit just under a 1/2 cup)