Grilled potato salad with grilled lemon, spring onions and mustard vinaigrette

Boil the Yukon gold potatoes until tender, cooked enough to eat but not mash-soft; split them in half and toss with olive oil.

Make the dressing: olive oil, whole-grain mustard, chopped parsley and shallots.

Put the lemons on the cooler side of a two-level fire.

Season the potatoes with salt and pepper and sear them cut side down on the grill, rotating them over the hot side, until crisp on both sides; return them to the bowl.

Grill the spring onions until charred outside and softened through; grill the lemons until brown and juicy.

Chop the spring onions and add them; squeeze in two of the grilled lemons, taste, and toss with the dressing.