Heat a skillet or griddle on medium heat while you mix the batter.
Combine the sourdough starter, sugar, milk, eggs, and vanilla in a large bowl and whisk until smooth.
Add the dry ingredients - flour, baking powder, baking soda, and salt to the wet ingredients and whisk until the batter is smooth.
You can make pancakes right away or let the batter sit at room temperature for a few hours if you'd like it to ferment. If you're ready to go right away...
Turn down the heat to medium-low heat, spread some coconut oil, olive oil, or melted butter to coat the surface of the skillet or griddle, and then ladle a half cup of batter onto the hot griddle.
Cook the pancakes for 2-3 minutes on each side. Look for bubbles around the edges of each pancake to know when it's ready to flip. When you see bubbles and the edges begin to look dry, use a spatula to slightly lift edge and check the first side. Once the first side is golden brown, flip and wait until the second side is golden brown as well, then transfer to a dish with a lid to keep pancakes warm while you finish the batch.
Serve warm with fresh butter, maple syrup, and whatever toppings you like. My favorite way to enjoy these pancakes is with whipped cream and fresh berries on top!