In a large mixing bowl, whisk together the all-purpose flour, sugar (if using), baking powder, baking soda, and salt until well combined.
In another bowl, mix the sourdough discard, egg, milk, melted butter, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Be careful not to overmix; a few lumps are perfectly fine.
Heat a non-stick skillet or griddle over medium heat. Lightly grease it with butter or oil.
Pour about 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface, then flip and cook until golden brown, about 2-3 minutes per side.
Serve your pancakes warm with your favorite toppings, such as maple syrup, fresh fruit, or yogurt.
Notes
Can adjust sweetness or add toppings like fruits or syrup.