Step 1

To make the sponge, stir down the sourdough starter, which can either be room temperature or cold if you keep it in the fridge. Add 1 cup of the unfed starter discard (now is a good time to feed your remaining starter) to a large bowl with the flour, sugar, and buttermilk. It will be quite thick. Cover and let sit overnight at room temperature or up to 24 hours in the fridge.

Step 2

The next morning, preheat your waffle maker. Add the eggs, melted butter, baking soda, vanilla, and salt to the overnight sponge, stirring until combined.

Step 3

Pour some of the batter into a waffle press and close the lid. Cook until golden brown and cooked all the way through. Transfer to a wire rack and keep warm in a 225 degree F oven while you repeat with the remaining batter until ready to serve.