When I told a friend recently that I was planning to go to a certain Barcelona restaurant that specialized in “molecular gastronomy,” he said, “Be sure to eat before you go.” I laughed, sort of, then remembered this meal enjoyed at a similar laboratory kitchen in northern Spain on an earlier trip. The place: Casa Marcelo, a relatively small and intimately lit room for which I’d had to make reservations well in advance. The menu was nine “courses” of small items like this one, called “Sardina en Lata” (canned sardine.) The food was beautiful and, warnings aside, satisfying in spite of a certain silliness. Huge plates with a teensy bullseye dollop of something, and often a title that took longer to read than it did to eat the serving. I remember feeling rewarded by a hearty tablespoon of a lamb-related confection toward the end, just before the “Piña Colada” appeared, the first of two desserts: pineapple sorbet topped by coconut cream that had been flash-frozen with liquid nitrogen moments before being tabled. The cost at this one-Michelin-starred restaurant, a well-worth-it 60 euros per person, plus drinks, tax, tip.