Caramelised Onion and Potato Salad

6 red onions, thinly sliced
1 kg new potatoes, unpeeled
30g (2/3 C) chives, snipped
4 rashers streaky bacon, rind removed
250g (1 C) whole egg mayonnaise
1 T Dijon mustard
Juice of 1 lemon
2 T sour cream
Heat 2 T oil in heavy-based frying pan and cook onion over medium-low heat for 40 minutes, until soft and caramelised. Cut potatoes into large chunks. Cook in boiling water for 10 minutes until just tender. Grill bacon until crisp, drain and chop roughly when slightly cooled. Put potato, onion and most of chives into large bowl and mix well. Add whisked mayonnaise ingredients and toss. Sprinkle with bacon and leftover chives.