Preheat oven to 425 degrees F and spray non-stick 12 muffin tin with cooking spray. Set aside.
In a large mixing bowl, add milk, lemon zest and lemon juice. Whisk and let mixture stand for 10 minutes. It should curdle somewhat and become sour milk.
Add egg, oil, maple syrup, vanilla extract, baking powder, baking soda and salt. Whisk well until combined and no small lumps are visible. Add flour and mix gently with spatula just enough to combine. Do not overmix and a few white flour patches are fine.
In a small bowl, combine blueberries and 1 tablespoon of flour. Stir to coat, add to a muffin batter and fold a few times until incorporated.
Distribute batter evenly between 12 openings of a muffin tin (I used regular ice cream scoop) and bake for 7 minutes minutes. Then reduce heat to 350 F and bake for another 13-15 minutes or until a toothpick inserted in the center comes out clean.
Remove lemon blueberry muffins from the oven and let cool for 10 minutes. Enjoy!
Notes
Store: On a plate on a kitchen counter covered with a towel for first 2 days. Then transfer muffins to a container with a lid and into the fridge for another 3 days.
Freeze: Bake, cool and place muffins in an airtight container. Freeze for up to 3 months. To thaw, just place one muffin on a counter for a few hours or microwave.