This stunning spring salad, full of peppery radishes, sliced celery, celery leaves and crunchy snap peas, is perfect for entertaining. If you grow your own celery, you'll have plenty of leaves to work with. But we found that most store-bought celery yielded enough leaves for this recipe if you combine the dark outer leaves with the pale yellow inner leaves at the heart. If you can't collect enough celery leaves, make up the difference with extra parsley. The results will still be delicious.