Broad Bean, Baby Beetroot, Celeriac & White Onion Salad with Walnut Cream Vinaigrette

This elegant salad calls for the tiniest beetroot you can find, preferably both golden and purple varieties. Generally small pickling onions are graded randomly, but again look for the smallest or cut the larger ones in half from the top to root end after they are cooked. The vinaigrette is unusual since it uses crème fraîche as well as walnut oil. If using shaved iceberg it should be placed on the plates before the broad bean mixture. Very suitable to pre