As I mentioned, when baking, I really like to weigh ingredients, especially flour. It really makes the process go so much faster–just pour into mixing bowl and there are fewer dishes to wash! Importantly, it also eliminates the tendency to get too much flour in the measuring cup, leading to a heavier baked good. So, weigh or carefully measure the flours into a large mixing bowl. Add oats, sugar, flax meal, baking soda, baking powder, and salt. Mix thoroughly, then make a little well in the middle to pour your wet ingredients. Combine buttermilk and egg. Pour into well in dry ingredients and blend, folding carefully until mixture is just combined. Avoid over-mixing: this will improve the texture of the finished product.