1/2 cup Sourdough Starter Sourdough Starter (http://www.marthastewart.com/255068/sourdough-starter)
2 tablespoons cornmeal
1/2 teaspoon salt
1/2 cup vegetable oil
3 large eggs, separated
1 teaspoon baking soda
Unsalted butter, for serving (optional)
Whipped cream, for serving (optional)
Fruit preserves, for serving (optional)
Maple syrup, for serving (optional)
Vegetable cooking spray
In a medium bowl, combine flour, sugar, and 1 1/2 cups warm water. Whisk until well combined and no lumps remain. Add more water if necessary to achieve the proper consistency. Add sourdough starter, and whisk to combine. Cover batter with plastic wrap, and let sit at room temperature (place it in the sink in case the batter bubbles over), for at least 12 hours.
Heat a nonstick waffle iron. Remove 1/2 cup batter, and add to remaining sourdough starter to keep the starter alive.
Add cornmeal and salt to batter, and whisk to combine. Whisk in oil and egg yolks. Combine baking soda with 1 tablespoon water, and stir into batter. In a separate bowl, whisk egg whites to stiff glossy peaks, then fold into batter.
Spray the waffle iron with cooking spray. Spoon in batter to fill but not overflow iron. Close lid; bake until no steam emerges from waffle iron, 3 to 5 minutes. Quickly flip the waffle back and forth between hands to cool it and to ensure an even crispness on both sides. Repeat with remaining batter. Place the waffles on serving plates. Serve with desired toppings.