Make batter. In a large mixing bowl, combine all the dry ingredients: flour, sugar, salt, baking powder, and baking soda. Whisk together the wet ingredients in a medium mixing bowl: sourdough starter, egg, milk, and vegetable oil. Pour the wet ingredients into the dry ingredients and gently mix until just combined. Be careful not to overmix; a few lumps are fine.
Cook. Heat a cast iron skillet or another heavy pan over medium-low heat. Once the pan is hot, add a tablespoon of butter and let it melt. Scoop the batter into the hot pan using ¼ cup to ⅓ cup amounts, depending on your desired pancake size. When bubbles form on the surface, flip the pancakes and cook until golden brown. Repeat in batches, wiping out the skillet with a paper towel between batches if needed.
Serve. Serve the pancakes immediately with syrup and butter or whipped cream and fruit for a special touch.
