Preheat the oven to 375 degrees F. Line a stoneware muffin tin with 9 parchment paper muffin cups.
In a large mixing bowl, beat together the melted butter, eggs, egg whites, vanilla extract, and maple syrup.
Add the oat flour, flax seeds, coconut sugar, baking soda, baking powder, cinnamon, and salt. Stir until combined then add the water. Stir until combined and lastly, fold in the blueberries.
Divide the batter evenly between the muffin cups, filling each cup full. Bake for 18-20 minutes. Cool for 10 minutes before moving the muffins to a cooling rack to finish cooling.