Why are cupcakes so trendy? Is it the whole Magnolia Bakery thing in NYC? Whatever it is, you can’t deny that cupcakes are good. Local Philly fav Brown Betty in NoLibs, is opening Brown Betty Petite today in Rittenhouse. The petite size shop only serves cupcakes, but they’re not your plain ‘ol vanilla and chocolate. The store offers everyday favorites like red velvet with cream cheese frosting and vanilla poundcake. And, on certain days of......