It was La Crossing Nostra. The 86-year-old man who was decapitated by a truck that plowed into him at a Brooklyn crosswalk is a former acting captain for the Genovese crime family, The Post can exclusively reveal. Anthony Conigliaro — a one-time mafioso known as “Tony Cakes,” “Tony the Dessert Man,” among other dessert-themed sobriquets — died June 12 in an accidental hit by a city Department of Transportation truck, his lawyers and law-enforcement sources said. “He spent his life looking over his shoulder but he forgot to look both ways before crossing the street,” one police source said.