Cupcakes/Muffins usually contain Sodium Aluminum Phosphate/Sulfate as a leavening ingredient, which can cause major health issues in high enough accumulations. Brownies usually only have Sodium Bicarbonate.
Actually it's an easy choice. I really don't get the cupcake craze. It's a small piece of cake, with less icing because there aren't any layers. Meh-cupcakes are dull.
http://i.imgur.com/QOSYj.jpg#...
2.cookies
3.brownies
yummy^o^