These sourdough waffles can rise overnight so you can quickly cook up a batch the next morning!
Whisk together the sourdough starter, buttermilk, flour, and sucanat until smooth. Cover and let sit on the counter overnight or 8-12 hours.
In a small bowl, whisk together the butter, egg, and vanilla. Whisk into the overnight sponge.
Sprinkle the salt and baking soda on top of the batter. Whisk until incorporated.
While you're mixing together the batter, preheat your cast iron waffle maker over medium heat on the stove for 5 minutes on each side.
When you're ready to cook, flip the iron so that the hot side is on top. Spray generously on both sides with avocado oil. Add about 1/2 cup of batter, close the iron, and cook for 1 minute. Flip and cook for 1 more minute, or until the waffle is a lovely golden color.
Remove waffle with a fork and eat immediately, or keep warm on a cooling rack-lined baking sheet in a 200 degree oven.
Flip waffle iron and preheat for 2 minutes. After 2 minutes, flip again so that the hot side is on top. Add more batter, close, and cook 1 minute. Flip and cook for 1 more minute.
Repeat the process of preheating for 2 minutes, flipping, + cooking for 1 minute per side until all of the batter is used up. Spray iron with avocado oil every few waffles, or after every waffle if they're wanting to stick.
*Active starter simply means that you have fed it about 8 hours beforehand. I suggest feeding your starter Friday morning, mixing up the sponge Friday night, and cooking the waffles Saturday morning.
*You can reheat any leftover waffles in a toaster.
*If you use the higher amount of salt, these waffles are quite salty. I personally prefer this to the lower amount of salt, but you might prefer the lower amount.
* Recipe adapted from NY Times.