These supersoft, pillowy chocolate muffins are reminiscent of your favorite chocolate doughnut, but with no fussy frying necessary. Packed with sour cream and just a drop of oil, they stay moist and delicious for days. They come together quickly in one bowl, so you can mix them up for a morning treat or afternoon snack without much effort. The cinnamon-sugar coating gives them a crunchy and lightly spiced exterior, which is a pleasing contrast to their soft centers, but they are just as…