Take three bowls. Add multi-grain idli flour in in two bowls and roasted rava in third bowl. Add yogurt and salt in each bowl. Grind spinach separately and carrot & beetroot together with very little amount of water. Adding beetroot gives a saffron color. Keep all of these aside. To prepare tadka, heat oil in a frying pan at medium heat. Once oil is hot, add cumin seeds and mustard seeds. Wait till starts crackling. Add chopped green chili and curry leaves in to it. Saute it for 30 seconds, add ginger and hing and saute it till ginger gets slightly brown. Add broken cashew-nuts and turn off the heat.