Stir the rolled oats and buttermilk together in a bowl and let the mixture stand for 10 minutes.
Whisk the egg, melted butter, and maple syrup into the softened oat mixture.
Whisk the flour, baking powder, baking soda, and salt in a second bowl, then fold the dry ingredients into the oat mixture just until no dry streaks remain.
Heat a lightly buttered skillet or griddle over medium heat.
Scoop about 1/4 cup batter for each pancake and cook until bubbles form and the edges look set, about 2 minutes.
Flip the pancakes and cook until the second side is golden and the centers are cooked through, about 1 to 2 minutes more.
Serve warm with maple syrup and berries.
Notes
Resting the oats in buttermilk softens them and gives the pancakes a tender, gently chewy texture.