In a large bowl, combine oats and buttermilk. Allow to sit at room temperature for 15 minutes for the oats to soften.
Add sugar, egg, melted butter, and vanilla to the oat mixture. Whisk until combined. Sprinkle the flour, baking powder, and salt over the top and mix with a rubber spatula or wooden spoon until combined. Be careful not to over mix. Set aside while you preheat your griddle.
Place a nonstick griddle over medium-low heat. Generously grease the griddle with butter. Using a ⅓ cup measuring cup (or an ice cream scoop), drop/pour the batter onto the griddle, slightly spreading it as you pour it**. Cook until golden brown, then flip and continue cooking until cooked through.
