Preheat oven to 350 degrees F. Prepare your muffin pan by buttering, spray with nonstick cooking spray or paper liners.

Sift the flour, baking powder, baking soda and salt into a large bowl.

In another bowl, whisk together the eggs and egg yolk until thoroughly mixed. Slowly whisk in the sugar, melted butter, milk and sour cream, vanilla and zest.

Add the wet mixture to the dry and using a rubber spatula, gently fold in the ingredients just until combined. Gently fold in the blueberries. Batter should be lumpy.

Divide the batter among the 12 muffin cups, filling them all the way to the brim. Bake in the center of the oven for 30 to 40 minutes or until the tops are golden brown and centers set. Use your finger to press the center. They are done when it springs back.