In a large bowl, combine the sourdough starter, flour, and milk. Mix until smooth.
Add the egg, sugar, and melted butter to the mixture. Stir until fully incorporated.
In a separate small bowl, mix the baking soda and salt.
Fold the baking soda mixture into the pancake batter gently.
Preheat a non-stick skillet or griddle over medium heat.
Add a small amount of butter or oil to the skillet.
Pour about 1/4 cup of batter for each pancake onto the skillet.
Cook until bubbles form on the surface, about 2-3 minutes.
Flip the pancakes and cook for another 2-3 minutes until golden brown.
Repeat with remaining batter, adjusting heat as needed.