1. Preheat oven to 200ºF. In a bowl, whisk together both flours, oats, cornmeal, brown sugar, baking powder, baking soda and salt. In a small bowl, whisk milk, yogurt, butter, egg and vanilla. Stir milk mixture into flour mixture until just combined.
2. Preheat a large skillet or griddle; mist with cooking spray. Pour batter 1/4 cup at a time, spreading gently. Cook until bubbles form on tops of pancakes and bottoms are light golden, about 2 minutes. Flip pancakes and cook until light golden and cooked through, 1 minute longer. Keep pancakes warm on a plate in oven while cooking remaining flapjacks.