Preheat oven to 400*. In small bowl, whisk flours, brown sugar, baking powder, salt, soda and flax. Stir in 2/3c granola.
In another bowl, whisk egg, buttermilk, and juices until blended. Add to flour mixture and stir just until moistened. May want to add 1/4c additional buttermilk. Fold in blueberries.
2
Fill greased muffin cups 3/4 full. Bake 12-15 minutes or until a toothpick inserted comes out clean. Cool 5 minutes before removing from pan to wire rack.
Note: if using frozen blueberries, stir in whil still frozen to avoid discoloring the batter.