Prepare your muffin pan by greasing each cup or placing muffin liners inside. Preheat the oven to 375 degree Fahrenheit (190 C). This is important to start with, as you don't want the batter to sit too long.
Make your own oat flour: Place 2 cups of rolled oats into a blender or food processor. Blend for 2-4 minutes until it becomes a sandy-like powder.
Whisk together the dry ingredients, the oat flour, baking powder, and sea salt. For more protein, add ⅓ cup hemp hearts.
In another large bowl mix together the applesauce, eggs, oil, sweetener of choice, and vanilla until well combined.
Pour the dry flour mix into the wet egg mixture, and add half the blackberries. Stir together just until mixed. Put batter into the muffin pan: a little less than ⅓ cup each to make 12 muffins. Distribute the leftover blackberries on top of the muffin batter.
Right away, place the muffins into the oven 375 degrees Fahrenheit (190 C) for 18-20 minutes until cooked (they will spring back to the touch). Let them cool for a few minutes before removing them from the pan.