In a large mixing bowl, combine the warm water and buttermilk. Stir in the active sourdough starter until well combined.
Crack the large egg into the mixture and add the olive oil. Whisk everything together until smooth.
In a separate bowl, combine the granulated sugar, fine sea salt, all-purpose flour, baking powder, and baking soda. Mix well to ensure there are no lumps.
Gradually add the dry ingredient mixture to the wet ingredients, stirring gently until just combined. Be careful not to overmix; it’s okay if there are a few lumps.
Cover the mixing bowl with plastic wrap or a clean kitchen towel and refrigerate overnight.
The next morning, heat a skillet or griddle over medium heat and lightly grease it with oil. Pour about 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface and the edges look set, about 2-3 minutes. Flip and cook for another 2-3 minutes until golden brown.
Serve the pancakes warm with your favorite toppings such as maple syrup, fresh fruit, or a dollop of yogurt.
