The day before you want to make the pancakes, take your sourdough starter out of the refrigerator and place on the counter.
In the evening pour the starter into a large bowl and add the lukewarm water and flour. Mix until combined, don't worry about lumps. Cover and place in a warm area overnight.
In the morning, remove 1 1/2 cups of sourdough (your starter) and put it back in your starter container and place back in the refrigerator.
Add the sugar, eggs, and melted butter into the sourdough batter and stir well until combined.
Add the baking soda and salt and whip until combined.
Heat a waffle iron until hot and spray with cooking oil.
Using a 1/3 measuring cup pour batter over a hot griddle or skillet. When the batter begins to bubble, flip the pancakes. Cook for another 1-2 minutes and remove. The pancake should be golden brown.