Put the potatoes in a pan of cold, salted water and add the turmeric. Bring to the boil and cook for 15-20 minutes or until a knife slides easily through the potatoes.
Drain well, then mash along with the garam masala, garlic granules and onion granules.
While the potatoes are cooking, mix the yoghurt with the mint sauce and sweetener, if using. Refrigerate until needed.
Spray a frying pan with low-calorie cooking spray, place over a medium heat and add the spinach. Stir it around in the pan, for 2-3 minutes until it has wilted, then allow to cool slightly.
Wrap the spinach in a clean tea towel and squeeze out any liquid. Roughly chop and stir into the potatoes along with the chopped coriander. Taste and season with a little salt, if required.
Divide the potato mix into 12 equal pieces, roll into a ball and flatten each into a small potato cake.
Wipe out the frying pan, and spray with low-calorie cooking spray. Place over a medium heat.
When hot, add the potato cakes and cook for around 3 minutes on each side until golden.
Serve with the yoghurt dip.