Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or lightly grease it.
In a large mixing bowl, combine the whole wheat flour, rolled oats, protein powder, brown sugar, baking powder, and salt. Stir until well mixed.
In another bowl, whisk together the applesauce, almond milk, eggs, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and mix until just combined. Be careful not to overmix.
Gently fold in the blueberries, ensuring they are evenly distributed throughout the batter.
Divide the batter evenly among the muffin cups, filling each about 2/3 full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.