Amazing Whole Orange Muffins

These fresh and simple muffins are some of the best I've ever tasted. They are not at all bitter, despite containing the skin and pith of an entire orange, and are a breeze to throw together. Thank you, food processor!   

Amazing Whole Orange Muffins
Adapted slightly from Fresh Orange Muffins by Lennie on Recipezaar
Makes 12 muffins
1⁄2 cup orange juice, not from concentrate
1 orange, cut into 6-8 chunks (skin on) and seeded
1 large egg
1⁄2 cup butter 
1 3⁄4 cups all purpose flour
2/3 cup granulated sugar
1 teaspoon baking powder
1 teaspoon baking soda
1/2 cup chopped bittersweet chocolate, optional
1/2 cup chopped or slivered nuts, optional

Preheat your oven to 400 and line or spray your muffin tin.

Add the orange juice to your food processor or blender. Cut the whole orange up (leaving the skin on!) into about 6 to 8 chunks, making sure to seed it if necessary, and puree with the OJ until smooth. The puree will still be fairly pulpy but that's fine. Add the egg and butter and whir to combine. 

Whisk together your dry ingredients in a separate bowl and then dump them into the wet, mixing until just combined. Fill each muffin tin equally and bake for about 20 minutes.