In a large bowl, whisk together the flour, baking powder, baking soda, sugar, and salt.
Add the sourdough starter, milk, vanilla, and egg to the bowl with dry ingredients. Mix well until combined.
Grease pancake griddle with butter or oil, heat skillet over medium-low. Ladle batter onto hot griddle. Cook until batter starts to bubble on top, then gently flip the pancake. Cook for an additional 1-2 minutes on second side.
Notes
Pancakes can be frozen once cooked. I usually pop them in a ziplock bag and store in the refrigerator.