Preheat the oven to 400°F. Line 12 muffin cups with paper liners, or spray with nonstick spray.
In a small saucepan, combine the milk, butter, orange zest and vanilla. Stir over medium heat until the butter melts. Cool until the mixture is lukewarm to touch. Beat in the eggs.
In a large bowl, whisk together the flour, sugar, baking powder and salt. Remove a heaping tablespoon of the flour mixture and mix it with 1⅓ cups blueberries in a small bowl; set aside. Add the milk mixture to flour mixture in the large bowl and stir just until blended. Gently fold in the flour-coated blueberries.
Divide the batter equally among the muffin cups. Sprinkle the rest of the blueberries on the tops of each muffin cup. Bake 16 to 20 minutes, or until golden and a tester inserted into the center comes out clean. Transfer to racks and cool.