Preheat oven to 375 degrees Fahrenheit (190 Celsius) and line the muffin pan with 12 parchment cups.
Prepare the dry ingredients first. In a large bowl mix flour, baking powder, baking soda together and put it aside.
Next work with the wet ingredients. In a medium bowl, mix butter and sugar together first.
Add the eggs and the lemon zest, and continue mixing until smooth.
Next, add milk and kefir or sour cream. Then add vanilla and mix it together with a spoon.
Combine both, the dry ingredients with the wet ones gently using a spatula or spoon. Don't over mix.
Finally, add the blueberries and mix it gently together.
Using a large spoon fill the muffin cups just below the rim and bake for 25-30 minutes. Or, until you see the blueberries starting to spill some of their juice.