In a mixing bowl, combine the sourdough discard, flour, sugar, baking powder, baking soda, and salt. Whisk together until well mixed.
In another bowl, whisk the egg, then add the milk and melted butter (or oil). Mix well to combine.
Pour the wet ingredients into the dry ingredients and gently stir until just combined. Don’t worry about small lumps; overmixing can toughen the pancakes.
Heat a skillet or griddle over medium heat and lightly grease it with butter or oil.
Pour about ¼ cup of batter onto the skillet for each pancake. Cook for 2-3 minutes, or until bubbles begin to form on the surface.
Flip the pancakes and cook for an additional 1-2 minutes, or until golden brown.
Keep the pancakes warm in a low oven while you cook the remaining batter.
Serve warm with your choice of maple syrup, fresh fruit, or yogurt.