Preheat oven to 350 degrees and lightly grease a donut pan with non-stick spray. Set aside.
In a medium bowl combine wheat flour, baking powder and salt. Set aside.
In a large bowl or stand mixer mash banana well.
Next, add in egg, sugar, milk, butter and vanilla to your mashed banana.
Now, slowly add in the flour mixture and mix until combined.
Fill your prepared donut pan with your donut batter. This should make ~6 donuts.
Bake for ~10-12 minutes or until donuts are golden brown and a toothpick when inserted comes out clean.
Allow donuts to cool fully before if you deciding to frost, glaze, or rolling in powdered sugar.
Enjoy!