Coriander seed Wholegrain mustard Olive oil White wine vinegar Chop the onion roughly and partially soften it in 2 generous tablespoons of the oil. Do not let it brown. Scrub the potatoes (but on no account peel them) and steam them. Wash and dry the sorrel, discarding tough stalks. Roll up the leaves tighly in your fingers, just a few at a time, as though making a cigarette, and snip across into fine ribbons. Tip the softened onion and its juices into a big bowl. Stir in half teaspoon each vinegar and mustard, some salt and lots of pepper and coriander seed. The coriander seed should be freshly toasted and ground coarsely using a pestle and mortar or a spare peppermil. Add the potatoes to the bowl while still piping hot, so they drink up the flavours of the dressing. Cut each potato in half or into quarters depending on size, and toss gently. Scatter some of the sorrel over the base of a shallow serving dish. Pile the potatoes into the centre, encircle them with the sliced salami and scatter the remaining ribbons of sorrel over the top. Serve while potatoes are still warm.