This is a special doorway. A lazy-Susan, really. Put your money down with your sweets order, spin it around, and the cloistered nuns turn it back to you with your pastries. No face to face contact, but they speak to you through their ancient recipes. In Palermo, visit the Cloister of Santa Caterina of Alessandria off of Piazza Bellini. Maria Oliveri and her team at I Segreti del Chiostro have preserved “The Secrets of the Cloister,” making the pastries using the nuns’ (I say) sacred recipes.
So, although this doorway is a thing of the past, your palette can still be reminded of what was (and what is!). When buying sweets here, you are supporting the restoration of the monastery and its soup kitchen.