To make the cupcakes:

Preheat the oven to 350 degrees F. In a small bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

Peel oranges (removing any seeds and as much of the white pith as possible) and puree in a blender or food processor. Measure out 1/2 cup of the liquid pulp. In the bowl of an electric mixer, combine orange pulp, eggs, buttermilk, vanilla, orange extract, sugar, and vegetable oil.

With the mixer on low, gradually add in the flour mixture, beating until just incorporated.

Fill your cupcake containers of choice a scant 2/3 full and bake 20-25 minutes, or until a toothpick inserted into the center comes out clean. Transfer cupcakes to a wire rack to cool completely before filling, frosting, or garnishing as desired.

To make the orange frosting:

In the bowl of an electric mixer, beat the butter at medium-high speed until creamy. Add half of the sifted sugar, the vanilla, the orange extract, and the orange juice. Beat until combined. Gradually add the remaining sugar until the frosting reaches your desired consistency.