Preheat the oven to 400 degrees F.
Line 12 muffin cups with paper liners.
In a small saucepan, combine the milk, butter, orange zest and vanilla extract.
Stir over medium heat until the butter melts; cool until the mixture is warm to touch; beat in the eggs.
Sift the flour, baking powder, sugar and salt into a large bowl.
Add the milk mixture and stir just until blended; fold in the blueberries.
Divide the batter equally among the prepared muffin cups.
Bake the muffins for about 15-20 minutes (until golden and the tester comes out clean)