This knobbly-looking root vegetable is not going to win first prize in any beauty competition, but there's so much more to celery root (celeriac) than meets the eye. Its delicate but distinctive flavor (think celery and parsley) works well with gentle spices and creamy sauces. Eaten raw, as in a classice rémoulade, it's beautifully crunchy, and it cooks to silky smoothness in a gratin – and it mashes beautifully too. An unsung hero of the vegetable patch.