Anyone strolling past Pasticceria il Boccione in the late afternoon might not see anything special. By that point, the window display set into its rust-colored, crumbling facade might very well be empty. Perhaps there will be one or two rounds of left-over crostata. But these, too, might mislead unknowing passersby: Burnt to a crisp on top, they look almost like mistakes. Like its humble exterior, the bakery’s blackened crostata hide delicious contents and serious history. Local legend holds that these crispy tops once served an important purpose: When a 16th-century…