In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.
In a medium bowl, mash the bananas until mostly smooth. Add sourdough discard, milk, egg, oil, and vanilla. Mix until well combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Do not overmix. Let the batter rest for 5–10 minutes while you preheat the pan.
Heat a lightly greased skillet or griddle over low-medium heat. Scoop about ¼ cup of batter per pancake onto the hot pan. Cook for 1-2 minutes, until bubbles form and the edges look set. Flip and cook for another 1–2 minutes until golden brown and cooked through.
Enjoy warm with maple syrup, fresh fruit, or your favorite toppings.