Cook the Sainsbury's British Gems New Potatoes according to the packet instructions. Drain and leave to cool.
Meanwhile, preheat the oven to 180 C (fan) and place the unpeeled garlic cloves in a small ovenproof dish. Pour in just enough olive oil to cover the garlic cloves. Pop the lid on the dish (or tightly cover with aluminium foil) and roast in the centre of the oven for 30 minutes. Alternatively, wrap the separated garlic cloves in foil and BBQ for 15-20 minutes.
When the garlic is cooked, remove from the oven and leave the lid on while the garlic cools completely.
Halve the cooked new potatoes lengthwise and brush the cut sides with a little of the garlic-infused olive oil.
Heat a grill pan to a high temperature on the hob and place the sliced new potatoes, cut side down, on the lines so that they grill nicely. Leave, without touching, for 6-7 minutes to get the lines. Alternately, do this on the BBQ. Remove from the heat and allow to cool completely.
Mix together the mayonnaise and yogurt. Squeeze in the roasted garlic using the back of a fork to mash everything together nicely.
Add 1 tbsp of the garlic infused olive oil and season well to taste.
Quarter or halve the grilled new potatoes and place into a bowl. Add the celery, spring onions, chives and parsley. Pour over the dressing and toss gently to coat. Taste for seasoning again and add more salt and pepper, if needed.
Transfer to a serving dish, sprinkle with more parsley and chives and serve!
Mum of three, daydream adventurer, OU Life Sciences graduate, occasional crafter, ex-pat Canadian & quite possibly Britain's most northerly food blogger.