Add the flour, Dutch-processed cocoa powder, sugar, baking powder, baking soda, and salt to a large bowl. Then, thoroughly mix these dry ingredients.
Add the eggs, unsweetened applesauce, milk, and vanilla extract to a separate large bowl. After that, thoroughly whisk these wet ingredients.
Add the dry ingredients to the bowl with the wet ingredients a little at a time. Mix to combine all the wet and dry ingredients, but don’t over-mix. *Sugar-free sweeteners tend to absorb more liquid, so if your muffin batter is too thick, add an additional 1-2 tablespoons of milk.
Wash and dry the fresh blueberries. Then, add about one teaspoon of flour to a bowl and lightly toss the blueberries in the flour. It helps remove moisture and prevents the blueberries from dropping to the bottom of the muffins.
Lightly fold the blueberries into the muffin batter.
Lightly spray a non-stick muffin pan with oil or add muffin liners to the pan. Then, pour the batter into the muffin pan to form about 10-12 muffins.
Bake the muffins at 350°F (177°C) for 20-23 minutes, or until a toothpick inserted comes out clean from the center of the muffins.
Let the muffins slightly cool, and enjoy!