While the chicken is cooking, peel and chop the potatoes and steam in the microwave on high for 6-8 minutes (adjust cooking time depending on microwave power) until tender. Or steam in a steaming basket on the stovetop for 8 – 10 minutes until tender. When tender, drain the potatoes, reserving 1/3 cup of cooking water. Then mash with reserved water, Parmesan and natural yoghurt. Season with salt and pepper.