Preheat oven to 350°. Spray a donut mold with cooking spray or line 2 baking trays with parchment paper and set aside.
In a large bowl combine all dry ingredients; whole wheat flour, almond flour, salt, and baking powder. Whisk to combine.
In a second medium sized bowl combine all wet ingredients; egg, milk, vanilla extract, pure maple syrup, and coconut oil. I recommend adding the coconut oil last so it doesn't harden.
Pour wet ingredients into dry ingredients and mix to combine. Fold in blueberries.
Pour batter into the donut mold or using a plastic sandwich bag, cut a tiny hole in the bottom corner. Scoop the batter into the bag and squeeze out the batter onto the prepared baking pan forming a circle to shape a donut. Top donuts with more blueberries, if desired.
Place donut molds on top of a baking tray for easy removal from the oven and bake for 15 minutes.
Meanwhile to make the glaze; in a small bowl mix powdered sugar, water, and pure vanilla extract. Mix well! I find it easier to drizzle the glaze on top of the donuts if you use a mixing bowl with a spout for easy pouring.
Remove donuts from oven and while still warm drizzle the glaze on top. Place donuts on a cooling rack and let cool.
Tip: Eat at least one donut warm :)