How to Make It
Preheat the oven to 425°F and spray a 9x13 sheet pan with cooking spray.
Combine the flours, sugar, baking soda, baking powder, and salt in a bowl. Stir with a whisk and set aside.
Separate the egg whites and yolks. Combine the yolks, buttermilk, milk, and oil and whisk to break up the yolk. Pour the liquid mixture into the dry ingredients and mix to combine. There will still be small lumps.
Place the egg whites in another bowl and beat until they have stiff peaks. Add about a third of the stiff egg whites to the batter. Stir to combine and lighten the batter. Add the remaining egg whites and gently fold with a spatula until no white streaks appear.
Pour the batter into the prepared baking sheet and top with whatever toppings you prefer.
Bake for 15 minutes, rotating halfway through. When the top is golden brown and the edges release from the sides of the pan, it’s done. To be extra sure, insert a toothpick into the middle of the pancake; it should come out clean. Cut into 8 even slices and serve with 2 teaspoons maple syrup or honey.