Toast the walnuts in a dry pan over medium heat for about 4 minutes, shaking the pan, until they smell toasty. Let them cool, then chop roughly.

Wash the parsley and dry it very well in a salad spinner or a clean towel; wet leaves water down the dressing. Pull off the thick stems, then chop the leaves and thin stems coarsely with a sharp knife. A few passes are enough: you want pieces of leaf, not a paste.

Cut the pomegranate in half across the middle. Hold one half cut side down over a bowl and tap the back firmly with a wooden spoon until the seeds fall out. Pick out any white pith.

Whisk the olive oil, lemon juice, honey, salt and a few turns of pepper (and the sumac, if using) in a small bowl.

Just before serving, toss the parsley, spring onion and pomegranate with the dressing. Scatter the walnuts on top so they stay crisp.