1.Boil, steam or microwave potato and kumara, separately, until tender; drain.
3.Place potato and kumara, in single layer, on oiled oven trays. Brush potato and kumara with a little of the oil; grill, in batches, until browned.
4.Meanwhile, combine remaining oil, onion, dill, basil, juice, capers, mustard and garlic in large bowl. Add potato and kumara; toss gently to combine.
Grilled kumara cubes can be tossed with a little fresh sage into a plain risotto just before serving, and the grilled kipflers go really well with a small grilled beef steak. Both can be cooked the day before you want to serve this salad and refrigerated overnight as the grilling sufficiently rewarms them.