Preheat the oven 400 degrees F. Line a standard 12-count muffin pan with paper liners and set aside.
In a small bowl, sift together the flour, baking powder, baking soda, and salt; set aside.
In a large mixing bowl, use a hand mixer to beat together the eggs and sugar for 3-4 minutes, until the mixture is light and fluffy.
Add the milk, vanilla extract and orange zest, mixing for 1 minute until incorporated.
With the mixer running, pour the butter into the batter in a slow stream until incorporated.
Fold in the dry ingredients in 2-3 batches, being sure not to overmix. Let the batter rest for 15-20 minutes.
Fill the prepared liners about ¾ of the way full. Place the pan in the oven and immediately reduce the heat to 350 degrees F.
Bake for 13-16 minutes, or until a wooden toothpick inserted in the middle comes out cleanly.
Allow muffins to cool in the pan for 5 minutes, then transfer to a cooling rack.
Notes
To store: allow them to cool completely, then carefully place them in an airtight container or plastic zipper bag. They will stay fresh for up to 3-4 days at room temperature.
To freeze: place them in a freezer-safe container or bag and freeze for up to 2-3 months. When you're ready to enjoy them, thaw them at room temperature for a few hours before serving.