1) Preheat oven to 400 degrees F. Lightly grease or butter a muffin tin.
2) In a food processor, plus oats until they are ground coarsely. You can also substitute 1 cup oat flour for this.
3) In a large bowl, mix together pulsed oats, flours, cinnamon, baking powder, baking soda, and salt.
4) In a smaller bowl, whisk together apple sauce, brown sugar, eggs, buttermilk, and melted butter.
5) Thaw blueberries and drain off any liquid. Toss blueberries with a tablespoon of flour.
6) Stir wet ingredients into dry ingredients and mix until just combined. Then fold in blueberries. Fill muffin tins with batter.
7) Bake muffins for 20-25 minutes at 400 degrees F. until muffins are puffed and browned on top.
Let muffins cool before serving. Store extras in an airtight container in the fridge or freeze them for longer storage.