Preheat your oven to 350 degrees. Line muffin tins with muffin liners.
Measure out and mix together the flour, sugar, baking powder, baking soda, and salt into a large mixing bowl.
In a separate bowl, mix together the buttermilk, cooled and melted butter, lemon zest, and eggs.
Make a hole in the centre of the dry ingredients and pour the wet ingredients into the well of dry ingredients. Mix with a fork until just blended.
Fold in the blueberries into the batter. Don't over mix!
Scoop the batter evenly into the prepared muffin cups, filling them 3/4 full.
Bake for 20-25 minutes