Make the dressing

Whisk together the mayonnaise and yogurt in a medium sized bowl or jug.

Season to taste with lemon juice plus a little salt and a good grind of pepper.

Put the raisins in a heatproof bowl and pour over boiling water from a kettle.

Leave to soak while you prepare the rest of the salad.

Put a frying pan over medium-high heat and add the walnuts.

Stir and turn the nuts until lightly toasted then take off the heat (2-3 min).

Leaving the peel on and discarding the cores, cut the apples into either thin matchsticks, half-moons or small chunks.

Put the apple pieces into a large bowl, squeeze over the lemon and toss well to prevent browning.

Use a potato peeler to remove any stringy bits from the celery then slice it thinly.

Add the celery to the apples along with the walnuts.

Drain the raisins and pat dry on kitchen paper. Add them to the bowl along with the herb if using and toss all the ingredients together.

Pour the dressing over the salad and toss well.

Taste and add more seasoning if needed.

If including the optional lettuce, use it to line a serving bowl or individual bowls, then pile the Waldorf Salad on top.

Best served straight away or can be stored in the fridge (without the leaves) for up to 24 hours.