This is not your usual potato salad. Bright spring onions, sweet blueberries and the smokiness they get from being cooked on the grill make this light and crispy side dish wonderfully unexpected and delicious.
For the dressing:1.
Preheat grill or grill pan to medium-high heat.2.
Toss the spring onion greens with 1/2 tablespoon of the oil and season with a pinch of salt. Grill until just charred, turning once, about 2 minutes.3.
Transfer the grilled onions to a blender or food processor and add the vinegar, miso, mustard, hot sauce and 3 tablespoons water. Puree until the mixture is bright green and smooth. Add the remaining 2 tablespoons oil and blend on high for 1 more minute. Season to taste with salt.
For the potatoes:1.
Fill a medium pot with room temperature water. Add a handful of salt to the water and then the potatoes. Bring the water to a rolling boil and then reduce the heat so that the water simmers. Cook until the potatoes are just fork-tender, about 15 minutes (they'll finish cooking on the grill). Drain the potatoes, and when cool enough to handle, cut in half lengthwise.2.
Take a large piece of aluminum foil, big enough for all the potatoes to fit face-down and still have enough left over to fold up the edges and place it on a sheet pan. Rub a thick layer of butter on the foil, leaving a 2-inch lip around the edges. Put the potatoes on the foil, flesh side down. Dot any remaining butter around the potatoes. Curl the edges of the foil up around the potatoes to help hold the melted butter in place.3.
Slide the foil and potatoes onto the grill and cook for at least 10 minutes. Check them occasionally to make sure they are browning but not burning. Flip the potatoes once the flesh is golden brown. Allow the skin side to cook for a few minutes before removing from the heat. Transfer the potatoes to a large bowl and toss with a liberal amount of the dressing.
For the salad:1.
Drizzle the spring onion bulbs and the blueberries with a little oil and sprinkle with salt. Put the quartered spring onions directly onto the grill (on a spot that isn't super-hot) and cook, turning occasionally, until evenly charred and tender, about 5 minutes. Slice them into bite-size pieces and add them to a bowl with the potatoes.2.
Use a grill basket or seafood pan to grill the blueberries. The berries will need no more than 2 minutes on the heat. They'll turn a darker blue color when they're done.3.
Put the dressed potatoes and spring onions on a platter. Top with the grilled blueberries and torn mint. Serve warm or at room temperature.