In a mixing bowl, combine the sourdough starter, flour, and sugar. Mix well and let it sit for about 30 minutes.
After 30 minutes, add the baking soda and salt to the sourdough mixture. Stir until well combined.
In a separate bowl, whisk together the egg, melted butter, milk, and vanilla extract.
Pour the wet mixture into the sourdough mixture and stir until you have a smooth batter.
Allow the batter to rest for 10-15 minutes. This will help the pancakes become light and fluffy.
Preheat a griddle or non-stick skillet over medium-high heat. Lightly grease it with butter or cooking spray.
Pour 1/4 cup portions of the batter onto the hot griddle. Cook until you see bubbles forming on the surface, then flip and cook the other side until golden brown.