Preheat waffle iron. Then, in a large bowl, whisk together the flour, baking powder, brown sugar, ground cinnamon, pumpkin spice and salt until combined. Set aside.
230 grams all-purpose flour, 12 grams baking powder, 40 grams light brown sugar, 3 grams salt, 1 gram pumpkin pie spice, 4 grams ground cinnamon
In a liquid measuring cup, whisk together the milk and pumpkin puree. Heat the mixture in the microwave until warm, not hot. To a medium bowl, add the pumpkin/milk mixture, melted butter, eggs, sourdough discard, and vanilla extract. Whisk until smooth.
240 grams milk, 240 grams pumpkin puree, 85 grams unsalted butter, melted, 110 grams eggs, 100 grams sourdough discard, room temperature, 4 grams vanilla extract
Pour the wet ingredients into the dry ingredients and whisk until just 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 instructions for how much sourdough waffle batter will fit. Mine fit just under a 1/2 cup)