We'll never forget the very moment we encountered the first shell peas of spring. There they were in a first-course salad at Osteria I Nonni: greener than Kermit the frog, springier than a spaniel off-leash, and as welcome, in the ice-capped late winter Minnesota landscape, as water is to a thirsty man. This spring mountain of peas was set on a dark bed of dressed arugula and further enhanced with thinly sliced red onions, chopped bundles of fried pancetta, and long, translucent papers of Parmesan. Every bite was charming: The sweet peas, the bitter arugula, the rich pancetta and cheese, and the point of raw onion allowed enough breadth that all the flavors could play off one another, like wildflowers in a spring field. This shell pea salad cost $9 and was worth every penny, because it was more than a salad, it was proof that spring would come--and what is the essence of a great salad, if not to pinpoint a fleeting moment in a season?