If you cannot get celeriac, finely sliced celery heart makes a good substitute.
Scrub and rinse the mussels very thoroughly under cold running water, knocking off any barnacles with the back of a knife blade. Tug off the ‘beards’. Discard any mussels that remain open when tapped. Put the mussels in a saucepan, cover tightly and place over a high heat. Steam for 2–3 minutes, until the mussels open. Discard any that remain closed. Remove from the heat, strain off the cooking liquor and reserve. When cool enough to handle, remove the mussels from their shells and place in a bowl of cool water to stop them drying out.
Slice or quarter the mushrooms and sprinkle some of the lemon juice over them. Peel the celeriac and cut into matchsticks, or shred in a food processor. Drop straight into water with lemon juice added to stop the celeriac discolouring while you quickly prepare the rest of the salad.
Arrange the mixed salad leaves on four plates. Peel and crush the garlic and stir it into the yoghurt or mayonnaise. Beat in the mustard and season with salt and pepper. Drain the celeriac and stir it into the dressing. Add the mushrooms. You can, if you like, add a little of the mussel liquor for flavouring. Spoon the celeriac and mushroom salad over the salad leaves. Drain the mussels, arrange these on top, and garnish with such fresh herbs as you have available.
© 1995 Frances Bissell. All rights reserved.