The piano was a grand, not a Steinway or a Fazioli, but like them it had a curve that made me want to trace its shape through the air with my finger. Despite its narrow legs, the piano did not teeter as the impeccable waiter carried it on a silver platter and set it down before me. I was 7 years old and sitting with my mother, as I did every afternoon that summer, at a small, round table at Confiserie Sprüngli in Zurich, perhaps the most famous temple of chocolate in Switzerland. Sunlight poured in through the tall second-floor windows, bathing the café in warmth and cheer.

The dessert was a masterpiece: a dark-chocolate body so smooth it glistened, white-chocolate keys, minor notes of a chocolate so dark as to be almost black, foot pedals brushed in gold leaf. Its lid was propped open on a thin rod, revealing an interior of milk-chocolate mousse so light that it vanished on my tongue, leaving an echo that lingers more than 40 years later. Adding to the magic was a small chocolate stool. I spent a few moments studying the fine treble and bass strings drawn across the mousse with, I imagined, the tines of a small fork. Later, I carefully wrapped the stool in a napkin and brought it to our hotel. My hunger for fantasy prevailed over my appetite.

We were not in Switzerland for happy reasons. My father, following a car crash in Spain, had been transferred to the intensive-care unit at a hospital in Zurich.