Step 1

Grind oats in a food processor until it resembles the texture of coarse flour, about 45 seconds. Add flour, whole-wheat flour, baking powder, baking soda and salt and pulse to combine. Add butter, and pulse until the mixture resembles coarse meal.

Step 2

Transfer the oat mixture to a large bowl, and make a well in the center.

Step 3

Whisk buttermilk and egg together in a glass measuring cup. Pour into the center of the well and gradually stir into the oat mixture.

Step 4

Heat non-stick skillet or griddle over medium-high heat until a bead of water sizzles and evaporates in a second. Brush some of the oil over the skillet or griddle. Ladle batter 1/3 cup at a time onto the griddle, spreading out into a circle and spacing to account for spread.

Step 5

Cook undisturbed, until the pancake bottoms are browned, most of the bubbles have popped and the edges are starting to dry out, 2 to 3 minutes. Flip and continue cooking until the other sides are browned, 1 to 2 minutes longer. Transfer to a plate or baking sheet to keep warm. Repeat with the remaining batter in several batches, re-brushing with oil as necessary and adjusting heat to prevent scorching.