Celery Root and Frisée Salad with Mustard and Capers

This is our update to céléri rémoulade, a classic French slaw-like salad of celery root with a mayonnaise-based dressing. Grainy mustard, lemon juice and capers add brisk, bright flavor that contrasts the natural sweetness of the celery root, fennel and apple. We like the curly, fluffy texture of frisée in this salad, but any variety of slightly bitter green works nicely.