Set aside the apple cider vinegar, milk and blueberries, mix all the other ingredients together in a large bowl until very smooth.
Add apple cider vinegar. Mix well. Allow batter to sit for 5-10 minutes while the coconut flour absorbs the liquid.
Add enough milk to reach the desired muffin batter texture.
Add blueberries and gently fold mixture to incorporate them.
Line muffin tins with paper liners or grease tins instead. Evenly fill 12 muffin cavities and bake for 22-25 minutes, or until golden brown.
Remove muffins from muffin pan right away to avoid soggy bottoms.
Notes
If you'd like to make this recipe for a keto or low carb diet, simply replace the maple syrup with the low-carb liquid or powder sweetener of your choice.
IF YOU USE POWDER (like monk fruit): You will need to add milk to the mix to bring the batter to the right texture. Add 1/4 cup of milk and mix, add another 1/4 cup if needed.
You can also use honey instead of maple syrup if you'd like.