Add grated coconut, green chillies, garlic, and cumin seeds to a small blender jar. Coarsely blend. Use only a spoonful of water, not more, if needed. Set aside.
Only use the leaves and thinner stalks of the amaranth greens. Rinse several times, then chop into thin strips.
Add oil to a pan and sauté the shallots until nicely browned. Add the amaranth and spread it out in the pan. Season with salt. Cover and cook, stirring occasionally – about 7 mins.
Take the pan off the heat and stir in the blended coconut paste. Let cool to room temp before stirring in the curd. Season with more salt if necessary.
Tempering: heat oil in a small pan and add mustard seeds and urad dhal. Once the dhal starts to brown, add dried chillies and curry leaves. Stir this into the raitha and serve.