Pre heat oven to 200C / 400F and line a large baking sheet with baking paper / silicon mat.
In small bowl, add the oil, turmeric, garlic, ginger and mix. Place the cauliflower on the baking tray and toss with the oil mixture. Keep mixing until all the florets are covered.
Arrange the florets so that they are evenly spread out and the cut parts of the cauliflower are face down.
Roast until lightly browned (around 30 mins). Half way through cooking, move the florets around so they are evenly cooked. Use a fork to check if the cauliflower is done, it should easily pierce the cauliflower
While the cauliflower is roasting, make the sauce. Toast the turmeric and curry powder together in a dry pan on a low heat for a couple of minutes.
Add the spices to the blender along with the coriander stalks, ginger, mango lemon juice and half of the yoghurt.
Blitz until smooth and then stir in the remaining yoghurt. (You can add all the yoghurt to the blender but it will make your dip very thin)
Serve cauliflower along with the tip and enjoy!