In a large bowl, combine all the ingredients except the baking powder and baking soda. Cover, and refrigerate the batter for up to 8 hours.
½ cups (180 g) all-purpose flour, 1 cup (227 g) sourdough starter, 1 tablespoon granulated sugar, ¼ teaspoon salt, 1 (50 g) large egg, 1 ½ cup (340 g) buttermilk, ¼ cup unsalted butter, 2 teaspoons vanilla extract
After 8 hours, sprinkle the batter with baking powder and baking soda. Stir well to combine. If needed, add 1 to 2 tablespoons of milk to thin out the batter.
2 teaspoons baking powder, ½ teaspoon baking soda
Heat a skillet or griddle over low-medium heat. Add a teaspoon or two of butter between every two to three pancakes. Allow the butter to melt, then add ¼ to ⅓ cup of the batter.
Cook the batter for 2 to 3 minutes. The pancake will have little bubbles over the surface and begin to crisp around the edges when it's ready to flip. Use a spatula to flip the pancake, then cook an additional 2 to 3 minutes on the opposite side. Repeat with the remaining batter.
Serve hot with fresh fruit and pure maple syrup. Store leftovers in the refrigerator for up to 3 days.