Add the flour, baking powder, baking soda, salt, and sweetener to a large bowl. Then, thoroughly mix to combine these dry ingredients.
Add the eggs to a separate bowl and whisk. After that, add the cottage cheese, milk, and vanilla extract to the bowl. Then, mix to combine the wet ingredients.
Add the wet ingredients to the bowl with the dry ingredients a little at a time until the muffin batter is fully incorporated. Don't over-mix the batter. *Sugar-free sweeteners tend to absorb more liquid, so if the batter is too thick, add an additional tablespoon of milk.
Wash and dry the fresh blueberries. Ensure they are completely dry and then place them in a bowl. Toss the blueberries with about a teaspoon of flour to help remove any excess moisture and prevent them from sinking to the bottom of the muffins.
Lightly fold the blueberries into the muffin batter.
Spray a non-stick silicone muffin pan with oil. Then, use a cookie scoop or measuring cup to pour the batter into the muffin pan, forming 12 muffins.
Bake these cottage cheese blueberry muffins at 350°F for 24-26 minutes, or until a toothpick inserted in the center comes out clean.
Once done, carefully remove the muffins from the pan and let them cool for at least 20 minutes before serving.