Boil the baby potatoes until fork-tender. Drain and let them cool.
For the minted yoghurt dressing: In a blender, combine the extra virgin olive oil, mint leaves, coriander leaves and stalks, sugar, apple cider vinegar and yoghurt. Blend until smooth. Adjust the consistency with additional olive oil if needed.
Heat a grill pan or barbecue. Grill the marinated chicken pieces until fully cooked and slightly charred on the edges. Set aside.
In a large salad bowl, combine the baby spinach, cherry tomatoes, red onion, cucumber, avocado, cashews and coriander. Add the boiled baby potatoes and grilled butter chicken to the salad.
Pour the minted yoghurt dressing over the salad. Toss gently to coat all the ingredients with the dressing.
To serve: Divide the salad among serving plates. Garnish with extra coriander if desired. Serve immediately and enjoy!