Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius) and spray an 8-inch square baking pan with non-stick cooking spray.

In a medium bowl, combine applesauce, sugar, and vanilla extract.

In a separate bowl, whisk together whole wheat flour, unbleached white flour, cocoa powder, baking powder, and baking soda.

Create a well in the center of the dry ingredients and add the wet ingredients.

Mix until just combined, being careful not to overmix.

Gently fold in the chopped walnuts and fresh or frozen blueberries.

Spread the brownie batter evenly into the prepared baking pan.

Bake for 25 to 30 minutes, or until a toothpick inserted into the center comes out firm and not sticky.

Let the brownies cool completely in the pan before slicing into 16 squares.

Enjoy!