Preheat oven to 350° and line muffin pans with 24 cupcake liners.
Cupcakes:
In large bowl, mix together flour, both sugars, baking powder, and salt.
In separate bowl, mix together wet ingredients: eggs, orange juice, milk, melted butter, and vanilla extract.
Add wet ingredients into large bowl and mix until combined. Do not over-mix.
Divide batter evenly into 24 liners (approx. 2/3 full). Bake for 26 - 30 minutes, or until a toothpick inserted into the center comes out clean. Cool on wire rack.
Icing:
In a small bowl, combine powdered sugar, zest from both oranges, melted butter, and orange juice until will mixed.
Dip each cupcake into icing, let extra drip off, then set upright on rack to set. Enjoy!
Notes
Freeze any leftover icing for later use. See blog for ideas.