Preheat oven to 350°F.
Line muffin pan with 12 paper liners.
Combine flour, sugar, baking powder, baking soda, and salt in a mixing bowl.
Place cream cheese, lemon zest and vanilla into the bowl of an electric mixer. Blend until smooth.
Add eggs, one at a time, beating until well incorporated.
Slowly add melted butter and milk, blending for just a few seconds.
Add the flour mixture, one cup at a time, and continue mixing until all ingredients are just incorporated (do not over mix).
With a spoon, fold in blueberries.
Pour an equal amount of batter into each lined muffin cup, filling about 3/4 full.
Bake for 30 minutes or until golden brown and toothpick inserted into the center comes out clean.
(Note - I have a picky kid who will not eat blueberry muffins if the blueberries are on top. I simply halve the batter and add blueberries to one half. Fill the muffin cups half way with the blueberry batter and then fill the top portion with the non-blueberry batter.)