Talk about good timing. Butter Lane co-owner Pam Nelson left Citigroup in January to open this tiny East Village cupcake spot with two friends. Fast-forward a year, and now her banker friends are "calling me about dishwasher jobs," she laughs. While diversification may be a financial-sector buzzword, in this case cupcakes are the sole attraction. Eschewing shortening (the name Butter Lane says it all) and food coloring, plus using suppliers like Organic Valley dairy and utilizing whole fruit and real vanilla, are the keys to these "cupcakes for adults." Rather than some of the overly sweet concoctions on the market, these cakes go for rich and nuanced rather than just saccharine. For those adults who prefer their cupcakes to come to them, bike delivery will start up soon. Anyone know an investment banker who likes fresh air and exercise?