Sourdough Waffles

 From: The New York Times 

For the overnight sponge, or base:

• 1 cup/240 grams sourdough starter “unfed”
• 1 cup/224 grams buttermilk
• 1 cup/120 grams all-purpose flour
• 1 tablespoon/about 13 grams light brown sugar

For the batter:

• 1 large egg
• ¼ cup melted unsalted butter or neutral oil
• ½ teaspoon vanilla extract
• ½ teaspoon/3 grams kosher salt
• 1 teaspoon/6 grams baking soda 

• Preparation

• Put the sourdough starter in a large bowl and add the buttermilk, flour and sugar, then stir to combine. Cover the bowl and allow it to rest overnight at room temperature.
• When you are ready to cook, whisk the egg, melted butter or oil and the vanilla extract together in a small bowl, then add the rested sponge. Add the salt and the baking soda to the batter and mix to combine.
• Pour some of the batter onto a preheated greased waffle iron and cook until the waffle is brown and crisp, then repeat.