When you’re Karen O of the Yeah Yeah Yeahs, your baby shower cake ain’t coming from Carvel. So her friends — including her Greenpoint-based stylist Christian Joy — tapped DJ/baker Justine D to make her a cake. Wait, “DJ/baker?” you say? Yep. The doyenne of dance, who has a monthly residency with Nancy Whang of LCD Soundsystem at the McCarren Park Hotel, graduated from the French Culinary Institute five years ago, and now she does pastries in addition to parties. “When called upon to do a baby shower cake for Karen O. of The YYY’s,” she writes on her site, “I knew it would be a Rock and Roll adventure complete with studs, fondant to look like leather and hand painted band pins.” Here’s a closer look at those studs.