Combine flour, sugar, baking soda, baking powder, and salt in a large mixing bowl; set aside.
Whisk together eggs, melted butter, oil, buttermilk, mashed bananas, and orange zest. Add to dry ingredients. Stir together lightly till ingredients are just combined.
Fill well greased or paper lined muffin cups. Bake at 350° for about 15 - 20 minutes.
In a small bowl, whisk together glaze ingredients till smooth. Glaze muffins while still warm.