Trim the dry ends from the rainbow chard then finely shred the stalks and leaves. Peel the red onion and thinly slice it. Zest and juice the lemon, keeping the zest and juice separate.

Place a large frying pan on the heat for a few mins. When warm, add the walnuts and toast them for 3-4 mins till darkened slightly and smelling nutty. Tip into a small bowl.

Place the frying pan back on the heat for a few mins. When warm add ½ tbsp olive oil and the onion. Fry for 3 mins to soften, then add the chard with a pinch of salt. Add the lemon juice. Cook together for 3 mins till the chard is wilted. Tip the cooked onion and chard into a bowl to cool.

Trim and thinly slice the celery. Place in a large bowl. Add 1 tbsp each cider vinegar, honey and olive oil. Add a pinch of salt and pepper and whisk well. Pour into the bowl with the celery.

Quarter the apples and slice out the cores. Slice the apples as thinly as possible and add to the bowl with the celery and dressing. Toss together to coat the apple to stop it browning.

Drain and rinse the lentils. Shake as much excess water off as possible and add them to the bowl with the apple. Give the bowl a stir.

Add the walnuts and lemon zest along with onion and chard mix and fold through. Taste and add more salt or pepper if needed and serve.