Preheat oven to 350 F, and grease a muffin tin or line with liners. (If using the oil-free option, they stick to the liners the first day.
The liners peel off easily after sitting a day, so you can either wait a day or bake sans liners.)
Set aside. In a large measuring bowl, whisk together the first 4 ingredients and let sit at least 10 minutes.
In a separate bowl, combine all remaining ingredients and stir well. Pour wet into dry, stir just until evenly combined, then portion into the muffin tins.
If desired, you can press a few chocolate chips into the tops of the muffins as well. Bake 14 minutes or until domed and a toothpick comes out mostly clean from the centre of a muffin.
Store leftovers in the refrigerator, and they are best eaten or frozen after 2-3 days.